469
FXUS61 KGYX 200727
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
327 AM EDT Thu Jun 20 2024

.SYNOPSIS...
Hot and humid conditions will persist today as a strong cold
front drops south over Northern New England this afternoon and
evening. This front will bring the risk for severe
thunderstorms and locally heavy rainfall. Cooler temperatures
and periods of showers are then likely to persist through the
upcoming weekend as a series of disturbances cross over the
region. Drier and warmer conditions will likely return towards
the middle of next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Nighttime microphysics satellite imagery early this morning
shows lingering upper level clouds across the north and
mountains with mainly clear skies over the foothills and points
south. Current temperatures are still primarily into the 70s
with a few locations in the 60s. Other than perhaps another
degree or two of cooling, temperatures will remain nearly
steady through daybreak as dew point depressions are quite
small.

Temperatures will quickly warm later this morning with the
increasing solar insolation with readings likely soaring into
the upper 80s to near 90 degrees by mid to late morning. Highs
will range from the 80s across the north due to additional cloud
cover to the middle and upper 90s south and then 80s along the
coast. Sfc dew points will remain elevated into the upper
60s/low 70s, which will help to boost heat indices into the
95-105 degree range. Based on latest guidance southern Oxford
County was added to the existing Excessive Heat Warning but
otherwise no changes were made to the heat headlines.

A sfc cold front is progged to arrive near the Canadian Border
at around 18Z this afternoon and then continue its southeastward
trajectory through the remainder of the afternoon and evening.
Strong sfc destabilization is expected ahead of this front with
MUCAPE climbing up to around 3500 J/KG. Bulk shear will be
modest at around 25 kts, but this is similar to yesterday where
the region experienced fairly widespread storm coverage despite
relatively weak forcing for ascent. As a result, expecting
greater storm coverage today given the extra forcing from the
advancing cold front. The main risk will be for locally damaging
winds given precip loading and high DCAPE but severe hail is
also possible within the stronger cells. The Storm Prediction
Center has placed most of NH along with southwestern ME into a
SLGT Risk (level 2 out of 5) for severe storms today with a MRGL
(level 1 out of 5) for the rest of the region. Went ahead and
added SVR wording into the grids to account for this.

Locally heavy rainfall is also possible given precipitable water
values between 1.5-2.0 inches and there is some training
potential with relatively short corfidi vectors and warm cloud
heights at around 10k ft. Antecedent conditions are overall dry
though and therefore any flooding should be localized. The
Weather Prediction Center has a MRGL risk for excessive
rainfall.

Latest CAM runs indicate storms will move offshore between 8pm
to 12AM tonight with perhaps just a few lingering showers
overnight. Lows will range from around 60 across the north to
the lower 70s south. Nighttime fog will be likely, especially
at locations that receive rainfall during the day.

&&

.SHORT TERM /FRIDAY/...
The cold front will stall somewhere between southern NH and
central MA on Friday as a wave of low pressure rides along it.
This will result in mainly cloudy skies, periods of showers, and
perhaps a few rumbles of thunder through the day. High
temperatures will be significantly cooler with northeast flow
prevailing with readings ranging from the 70s to low 80s from
north to south.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Periods of showers and storms are likely at times through the
weekend and into early next week as we find ourselves on the
northern side of the ridge. Cooler conditions are expected on
Saturday, but a warming trend resumes on Sunday with temps
warming into the 80s and continuing into early next week. Drier
conditions likely return by midweek next week as highs warm back
well into the 80s.

&&

.AVIATION /07Z THURSDAY THROUGH MONDAY/...
Short Term...Patchy FG will continue to result in localized IFR
to LIFR restrictions through around 12Z this morning, especially
at KLEB. VFR conditions and southwesterly flow will then follow
through early afternoon before a cold front drops south,
resulting in scattered strong to severe thunderstorms and
possible LIFR restrictions. Any storm will be capable of locally
strong winds, +RA, and GR. Storms clear by late evening with
just patchy FG overnight. Additional restrictions are then
possible on Friday as periods of SHRA persist under
Northeasterly flow. LLWS is not expected outside of TSRA.

Long Term...Periods of showers and storms bring restrictions at
times Friday night through Monday, especially in the afternoon
hours. Otherwise, mainly VFR conditions are expected. VFR
conditions likely then prevail next Tuesday and Wednesday.

&&

.MARINE...
Short Term...Southwesterly flow prevails today at 10-20 kts and
seas of 3-4 ft. Winds turn westerly late behind a cold front
tonight and then become northeasterly on Friday but remaining
below SCA levels. Showers and gusty thunderstorms are likely
late afternoon and evening .

Long Term...High pressure gradually builds in for the weekend.
SCA conditions are then possible next week as southerly flow
increases as the high moves offshore.

&&

.CLIMATE...
RECORD HIGHS FOR JUNE 20: Concord-98, 1993 Augusta-95, 1953
Portland-93, 2020

RECORD WARM LOWS FOR June 20: Concord-73 in 1931; Augusta-67 in
1974; Portland-69 in 2020

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Excessive Heat Warning from 11 AM this morning to 7 PM EDT
     this evening for MEZ012-018>028-033.
     Heat Advisory from 11 AM this morning to 7 PM EDT this evening
     for MEZ013-014.
NH...Excessive Heat Warning from 11 AM this morning to 7 PM EDT
     this evening for NHZ006-008>010-012>015.
     Heat Advisory from 11 AM this morning to 7 PM EDT this evening
     for NHZ002>005-007-011.
MARINE...None.

&&

$$

NEAR TERM...Tubbs
SHORT TERM...Tubbs
LONG TERM...Clair