Flash Flood Warning 3, NWS Caribou, ME

332 
WGUS71 KCAR 212001
FFSCAR

Flash Flood Statement
National Weather Service Caribou ME
401 PM EDT Sun Jun 21 2026

MEC003-212045-
/O.CON.KCAR.FF.W.0003.000000T0000Z-260621T2045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Aroostook ME-
401 PM EDT Sun Jun 21 2026

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 445 PM EDT THIS 
AFTERNOON FOR SOUTHEASTERN AROOSTOOK COUNTY...

At 401 PM EDT, Doppler radar indicated thunderstorms have produced 
heavy rain across the warned area. Between 3 and 4 inches of rain 
have fallen. Flash flooding is ongoing or expected to begin shortly. 
Subsequent storms could lead to further flooding.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Radar.

IMPACT...Flash flooding of small creeks and streams, urban areas,
         highways, streets and underpasses as well as other poor
         drainage and low-lying areas.

Some locations that will experience flash flooding include...
  Patten, Sherman, Island Falls, Haynesville, Reed Plantation, 
  Stacyville, Crystal, Weston, Reed, Hersey, Bancroft, Glenwood and 
  Silver Ridge.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

&&

LAT...LON 4597 6843 4604 6831 4574 6791 4567 6810
      4587 6838 4593 6843 4594 6843 4595 6843

FLASH FLOOD...RADAR INDICATED

$$

SM

243 
WGUS71 KCAR 212039
FFSCAR

Flash Flood Statement
National Weather Service Caribou ME
439 PM EDT Sun Jun 21 2026

MEC003-212049-
/O.EXP.KCAR.FF.W.0003.000000T0000Z-260621T2045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Aroostook ME-
439 PM EDT Sun Jun 21 2026

...FLASH FLOOD WARNING WILL EXPIRE AT 445 PM EDT THIS AFTERNOON FOR 
SOUTHEASTERN AROOSTOOK COUNTY...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures.

&&

LAT...LON 4597 6843 4604 6831 4574 6791 4567 6810
      4587 6838 4593 6843 4594 6843 4595 6843

$$

SM

Area Forecast Discussion
National Weather Service Caribou ME
539 AM EDT Sun Jun 21 2026

.WHAT HAS CHANGED...
- 6 AM Update: Increasing confidence in patchy to areas of fog
  developing tonight, especially in areas which receive rain
  today. Adjustments made to the aviation section below with the
  12z TAFs.

- Increasing confidence in track and timing of low Monday night
  into Tuesday.

- Increased winds and gusts with the Monday night system.

&&

.KEY MESSAGES...
1) Slow moving showers and thunderstorms today could lead to
localized significant rainfall.

2) A low pressure system passes through the region
Monday night into Tuesday, while track remains
uncertain.

3) Prolonged troughing in the Northeast will lead
to multiple rounds of showers and storms this week.

&&

.DISCUSSION...
KEY MESSAGE 1...Slow moving showers and thunderstorms today
could lead to localized significant rainfall.

KEY MESSAGE 1 DESCRIPTION...
Continued instability under the broad upper level trough will
support diurnal showers and storm development through the day
today. For the Central Highlands down through the Interior
Downeast region, 500 to 1000 J/kg of CAPE could be available for
supporting convective growth. Forecast soundings present this
CAPE in a tall, skinny manner, which can be indicative of
support for efficient rainfall processes. Additionally, PWATs
are forecast to sit around 1.1 to 1.2 inches. KCAR PWAT
climatology for today has 1.06 inches for the 75th percentile,
and 1.28 inches for the 90th percentile, with the forecast PWAT
for today falling between these two percentiles and being
marginal for efficient rainfall potential. Since the highest
CAPE values support convection closer to the Bangor region, will
consider the KGYX PWAT climatology for today as well, which has
1.22 inches for the 75th percentile and 1.47 inches for the 90th
percentile, so the forecast values for the Bangor area fall a
little short of the prime target for efficient rainfall
potential, which would be exceeding the 90th percentile.

Forecast warm cloud layer from forecast soundings is also below
what would be needed for efficient rainfall potential, with warm
cloud layer being forecast at around 5 kft, half of the 10 kft
that is textbook for tropical type rainfall rates.

Of highest concern though, given all that has been discussed
above, is the storm motion. With little to no steering flow,
any showers and storms that develop will be slow to move, and
likely to collapse near where they developed, leading to any
moderate rainfall to occur over the same area through the life
of the shower or storm. This environment could lead to localized
significant rainfall that may even result in localized ponding
in any poorly drained areas. Flash flood guidance does remain
high in the primary area of concern, with 1 hour FFG of 1.3 to 2
inches and 3 hour FFG 2 to 3 inches.

KEY MESSAGE 2...A low pressure system passes through the region
Monday night into Tuesday, while track remains
uncertain.

KEY MESSAGE 2 DESCRIPTION...
Shortwave moves through region Monday afternoon into Tuesday
evening. With this system, moisture quickly increases throughout
Maine, and rain showers, with an isolated thunderstorm, are
possible, mainly to the north. Models seem to favor the general path
of the low pressure staying just south of Maine, but there is
uncertainty in the exact track. Models have better agreement on
timing of system. Models that seem to have a more southern low
pressure system, bring less precipitation to the Downeast
region, while models favoring a farther north low pressure
system, bring more precipitation to the Downeast region. Global
models seem to be trending northeast with the low, bringing more
rain to the coastline. Stuck with the NBM again for this
update, since it shows the general trend well between models.
The best chance for precipitation is going to be interior and
coastal Downeast, with gradually lighter showers expanding
farther inland. How far inland the precipitation reaches, is
going to depend on the track. Looking at between 1 to 1.5 inches
of rain possible Downeast.

Minimal instability could lead to some isolated thunderstorms in
the Central Highlands and northern regions Monday afternoon as the
low approaches from the southwest. Southerly flow should keep
Downeast stable enough to avoid convection. Around 500 J/kg of
CAPE, and some decent low-level lapse rates could get some
thunder rumbles over the region in the afternoon. Decreased
thunder chances however, since shear and helicity look weak, and
some CIN is present. Will have to continue to monitor to see
how trends progress.

KEY MESSAGE 3...Prolonged troughing in the Northeast will lead
to multiple rounds of showers and storms this week.

KEY MESSAGE 3 DESCRIPTION...
Positive PNA pattern over the Atlantic parks a high pressure
system over the west, resulting in prolonged troughing over the
region, with multiple rounds of rain showers moving through.
Cool temperatures generally in the 70s. Overnight lows generally
in the 50s. Prolonged trough results in multiple rounds of
showers, with chances for thunderstorms each afternoon.

&&

.AVIATION /09Z SUNDAY THROUGH THURSDAY/...
Today...VFR conditions continue across all terminals. Scattered
showers and thunderstorms this afternoon, particularly from
KGNR down through KBGR and throughout the Downeast region. Winds
light and variable.

Tonight...Mostly VFR conditions continue across all terminals,
though there is increasing likelihood of fog building in after
midnight, limiting visibility to IFR/LIFR late at terminals
which see rainfall during the day. Winds light and variable.

Monday - Monday night...MVFR/IFR in rain showers at all
terminals, and with a chance of thunderstorms at
KFVE/KCAR/KPQI/KHUL. S winds at 5 to 10 kts, becoming E at 5 to
10 kts overnight. Fog possible at all terminals Monday night,
with KBGR and KBHB possibly in thicker fog.

Tuesday - Tuesday night... MVFR/IFR in rain showers at all
terminals, and with a chance of thunderstorms at
KFVE/KCAR/KPQI/KHUL. Improving to VFR late afternoon, though
fog could lower visibility at all terminals Tuesday night. E/SE
winds at 5 to 10 kts, gusting to 15 to 20 kts, shifting to NW 5
to 10 kts.

Wednesday - Wednesday night...Mainly VFR. Possible MVFR at
KFVE/KCAR/KPQI/KHUL in the afternoon with showers and chance of
thunderstorms. NW winds at 5 to 10 kts. Become light and
variable overnight.

Thursday...Possible MVFR at KFVE/KCAR/KPQI/KHUL, in the
afternoon with showers and chance of thunderstorms. S/SE winds
at 5 - 10 kts.

&&

.MARINE...
Winds remain below 25 kts and seas less than 5 ft across all
waters today through tonight. Below SCA conditions Monday. Seas
creep up to 5 ft on Tuesday into Wednesday. Rain and patchy fog
Monday night into Tuesday. Chance for thunderstorms Tuesday.
Winds early Tuesday could be about 20 kt, with some gusts 25 kt
to near 30 kt. S winds on Monday, shift to the NW on Tuesday
night.

&&

.CAR WATCHES/WARNINGS/ADVISORIES...
ME...None.
MARINE...None.

&&

DISCUSSION...AES/JMM
AVIATION...AES/JMM