First Nor'Easter Of The Season Forming
480
FXUS61 KCAR 240022
AFDCAR
Area Forecast Discussion
National Weather Service Caribou ME
822 PM EDT Wed Sep 23 2026
.WHAT HAS CHANGED...
- Updated aviation discussion.
&&
.KEY MESSAGES...
1) Potential for frost tonight inland from the coast and north.
2) A coastal low will impact at least Downeast Maine late this
week.
&&
.DISCUSSION...
KEY MESSAGE 1...Potential for frost tonight inland from the
coast and north.
KEY MESSAGE 1 DESCRIPTION...
The Frost Advisory has been expanded to include interior Hancock
and central Washington counties. Surface 1040mb high pressure
is centered over Quebec this afternoon, with upper level high
pressure building into the region from Ontario. This pattern
will continue tonight, resulting in clear skies and light winds,
similar to last night. Once again this should result in a cold
night, frost, and river valley fog. A modifying air mass could
limit how low temperatures fall tonight, but lows in the 30s are
expected outside the Downeast Coast. Northern areas of Maine
will likely reach freezing or below freezing. While not as cold
as tonight, Thursday night could see additional patchy frost
and fog, mainly in northern areas as clouds increase from the
south.
KEY MESSAGE 2...A coastal low will impact at least Downeast
Maine late this week.
KEY MESSAGE 2 DESCRIPTION...
A coastal low is expected to develop across the Mid-Atlantic
region late this week while high pressure remains centered over
Quebec. The timing and track of the ocean low is still uncertain
with blocking high pressure to the northwest of our forecast
area and ridging across the Great Lakes. Latest ECMWF guidance
delays the onset of rain into the weekend as the blocking high
remains resolute over Eastern Canada. This will result in
additional uncertainty in how close the low will pass to the
coast which will determine how far north the precipitation will
reach. Regardless, northerly to northeasterly winds will become
gusty over the weekend, especially along the coast, as a tight
pressure gradient forms. General trend currently is that the low
pressure system will continue to move southwards due to the
high pressure, with majority of the rain staying over the waters
and the Downeast region.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
Tonight...Variable conditions in patchy fog late. Otherwise,
VFR. Light and variable winds.
Thursday...Variable conditions in patchy fog early. Otherwise,
VFR. Variable winds 5 to 10 knots.
Thursday night...Variable conditions in any patchy late night
fog, otherwise VFR. North/northeast winds 5 to 10 knots.
Friday - Monday...VFR north. VFR/MVFR Downeast with likely
rain. Across northern areas, N/NE winds 5 to 10 knots, becoming
NE Sunday. Across Downeast areas, N/NE winds 10 to 15 knots
with gusts up to around 20-25 knots at KBGR, and 30 knots
possible at KBHB Saturday and Sunday afternoon. Winds diminish
Sunday night back to 10 to 15 knots.
&&
.MARINE...
Winds/seas below small craft advisory levels tonight through
Thursday.
Northeast winds and seas increase to gales late Thursday night
into Friday, winds peaking around 45 knots in the outer waters
and around 40 knots in the coastal waters by Friday night. A
gale watch is now in effect from 8AM on Friday in outer waters
and from 5PM in coastal waters and will persist through at least
8PM Sunday night. Gales remain possible in the intracoastal
waters. Peak wave heights in the outer waters will be around 11ft
to 16ft, and around 7ft to 12ft in the coastal waters.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...Frost Advisory from midnight tonight to 7 AM EDT Thursday for
MEZ015>017.
MARINE...Gale Watch from Friday afternoon through Sunday evening for
ANZ050-051.
Gale Watch from Friday morning through Sunday evening for
ANZ080-081.
&&
$$
DISCUSSION...ASB/JS/MB/CN
AVIATION...ASB/JS/MB/CN
Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
405 PM EDT Wed Sep 23 2026
Valid 00Z Thu Sep 24 2026 - 00Z Sat Sep 26 2026
...Significant Heavy Rainfall/Flooding Threat across New Mexico and the
Southern High Plains through tomorrow...
...Developing coastal low spreads coastal flooding, rip currents, wind
gusts, and heavy rain along the East Coast this week...
This afternoon, satellite imagery depicts a plume of tropical moisture
streaming northward into the Southwest and Southern High Plains in between
a trough over Baja California, and an upper-high in the western Gulf. The
persistence of this pattern will fuel the threat for impactful flash
flooding over portions of Central New Mexico and the Southern Plains today
and tomorrow, especially in light of yesterday's rainfall. The greatest
coverage of heavy rainfall and flash flooding is expected later today into
the overnight hours, where some areas could see storm total rainfall of
2-4" on top of what fell yesterday. As such, locally significant and life
threatening impacts are possible, particularly across sensitive terrain,
urban areas, and burn scars. Tomorrow, rainfall coverage will decrease
somewhat, although significant flash flooding certainly remains possible
as any additional rain atop inundated soils will quickly translate to
runoff. Accordingly, Flood Watches are in affect through Thursday evening.
Further to the east, Sufficient moisture and slow-moving storms may lead
to flash flooding concerns across portions of the Ohio/Tennessee Valley
into the Mid-Atlantic and Southeast along an inverted trough axis this
afternoon.
Meanwhile, a strong coastal low is expected to rapidly spin up in the
western Atlantic over the next 24-36 hours and approach southern New
England by Friday. This system will usher in a swath of hazardous weather
to portions of the East Coast, including significant coastal flooding, rip
currents, wind gusts in excess of 45 mph, and heavy rainfall. Coastal
residents are encouraged to heed local National Weather Service forecasts,
warnings, and the latest WPC Key Messages for this system at
wpc.ncep.noaa.gov.
Another strong system is forecast over the Pacific Northwest late
tomorrow, which will usher in soaking rains through Friday. As this
system intensifies, expanding coverage of showers and thunderstorms will
support at least an isolated risk of heavy rainfall over the Heartland on
Friday. In its wake, cooler than average temperatures will begin to set in
over the Northern Tier by Friday-Saturday.
posted by Advackia at 6:48 PM
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