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Area Forecast Discussion (AFD)

Issued by Caribou, ME (CAR)

                            
000
FXUS61 KCAR 171056
AFDCAR

Area Forecast Discussion
National Weather Service Caribou ME
656 AM EDT Wed Jul 17 2019

.SYNOPSIS...
A cold front will cross the region today and will push off the
Downeast coast this evening. High pressure follows for Thursday
and moves east of the region Friday. A cold front will cross 
the area Saturday and will be followed by a weak low Sunday.

&&

.NEAR TERM /THROUGH TONIGHT/...
655 am update...
Dwpts hv risen into the m60s acrs the entire area as wmfnt lifts
thru. Area wl be in wmsector tda with cdfnt currently appchg the
Gulf of St. Lawrence. MUCAPE of 500 Joules being shown ovr nrn
zones this mrng. Regional radar at 1045z shows spotty showers
working thru interior Downeast this mrng with main rain area mvg
into Vermont ahd of s/wv. Latest hrrr conts to handle showers wl
this mrng with rain lkly mvg into Downeast btwn 15z-16z based on
current mvmnt. 

Question then bcms if this rain wl stabilize airmass ahd of
cdfnt as convection dvlps ovr nrn areas and heads south. Latest
hrrr has trended down a little on storm potential but wl retain
sctd thunder with hvy rainfall for srn zones this aftn. Later
shifts can monitor potential. 

Prev discussion blo...
Warm and humid airmass rmns locked in acrs the entire area this
mrng. Initial s/wv mvd thru nrn zones bringing showers with
embedded storms quickly thru early this mrng and hv since mvd
into NB. Addn'l showers are dvlpng acrs far wrn Quebec as of 08z
as another subtle wv rotates thru and acts on area of warm 
advection.

Sfc cold front currently located ovr swrn Quebec and dropping
south. This wl set the stage for dvlpmnt of showers and
thunderstorms this afternoon. CAPES fcst to range fm 1500-2000
Joules ahd of the front. Realized instability wl depend on how
much htg we can achieve in moist airmass. 

PW values will increase abv 2 inches in the Downeast areas aft
15z this mrng. Storms that dvlp wl be efficient rain producers
with potential for torrential downpours. Wl retain locally hvy
rainfall with line of convection as it dvlps aft 18z. Risk for
flash flooding looks to be low at this time with 1-hr FFG
greater than 1.5 inches. At this time, storms look to be fairly
progressive but hv continued mention of minor flooding in HWO. 

As for strong storm potential, hv opted not to include gusty 
winds in fcst for srn zones. 0-6km bulk shear progged to range
fm 30-35kt for a period of time this aftn, tho does not appear
to be aligned with convection timing.

Cold front wl mv offshore this evng leading to much more
comfortable conds as dwpts finally drop into the 50s. Mins by
Thur mrng expected to dip into the 40s acrs the Crown of Maine
and m/u 50s for Downeast.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY/...
High pressure will move out of Quebec and across Maine Thursday. 
Thursday will be sunny and seasonably warm with comfortably low
humidity levels. The high slides east of the region Thu night 
as a weak low tracks well south of the area along the remains of
the front that crosses our region in the near term. It will not
be as cool Thu night with the weak return flow and an increase 
in the dew points. A bit of patchy late night fog will be 
possible along the coast. Friday will be warmer and turning much
more humid with dew points to climb back into the l/m 60s. It 
will be a partly sunny day with highs in the low to mid 80s 
inland, but cooler along the coast. A shower or thunderstorm is 
possible during the afternoon, mainly to the north and west of 
the Katahdin Region.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
Friday night will be warm and muggy with patchy fog possible along 
and near the coast.  A weak disturbance ahead of a cold front that 
will be organizing to the north of the Saint Lawrence River may 
produce scattered showers.  The cold front is expected to cross the 
FA Saturday, but there are some differences in the timing and 
strength of the front amongst the models. Saturday will likely 
be the hottest and most humid day of the week with highs likely 
to get into the low to mid 90s for interior Down East/Bangor 
ahead of the front, and heat index values will likely get into 
the upper 90s. A heat advisory will likely be required down the
road. There will certainly be plenty of low level juice with 
dew points AOA 70F and PWATs around 2". The amount of 
instability will be dependent on the timing of the front, but 
given the significant low level moisture and time of year there 
will be the potential for some stronger storms, and possibly 
severe storms too. Any storms that do develop will contain 
torrential downpours. For now, given that it is still day 4, 
will hold off on any enhanced wording. In the wake of the front,
it will turn less humid Sunday. Sunday through Tuesday will 
feature more seasonable temperatures and more comfortable 
humidity levels as the eastern Great Lakes and northeast U.S. 
will be under the influence of an upper low across northern 
Quebec and a trough that will extend south into our region. 
Although a few showers can't be ruled out, much of the time Sun-
Tue will be rain-free. The most likely time for showers will be
Sunday afternoon when a disturbance may cross the area.

&&

.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
NEAR TERM: IFR restrictions present at FVE this mrng thru 12z in
low clouds and fog. All other terminals start off VFR, though
likely to see MVFR move in at CAR and PQI after 08z with vcsh
present. Cannot rule out vcts in the afternoon at CAR and PQI
for a few hours. Most likely area will be from HUL and south in
the afternoon as cold front moves through. All sites VFR after
18z with the exception of BHB. 

SHORT TERM: Outlook Thu-Sun

Thu & Thu night...VFR, except local IFR possible at KBHB in 
patchy fog Thu night. 

Fri...VFR, except for local MVFR in any showers/t-storms in the 
afternoon from KHUL north.  

Sat...Variable conditions with scattered showers and t-storms. 
Gusty and erratic wind & hail possible in t-storms. 

Sun...VFR with local MVFR in any showers.

&&

.MARINE...
NEAR TERM: Winds and seas will remain below SCA levels though
seas will increase to 3-4ft this aftn in srly swell. Expect that
patchy fog will plague the waters today before clearing as cold
front crosses the water. Thunderstorms can be expected late this
afternoon and evening. 

SHORT TERM: The wind and seas are expected to remain below small craft 
advisory levels through the weekend.  Some patchy fog is possible 
late this week into Saturday morning as a warm/humid air mass is 
across the colder ocean waters.  The most likely times for fog will 
be overnight into the early morning hours.

&&

.CLIMATE...
Near record high temperatures possible Saturday. The record 
high temperature in Bangor on Saturday, 7/20 is 96F set in 1991.
In Millinocket, the record high on 7/20 is 93F set in 1991. The
records in Caribou and Houlton appear to be out of reach at 
this time. 

Near record warm low temperatures are possible Saturday 
morning, but with the cold front coming through temperatures
will likely drop off enough during the evening hours that 
records will not be set.

&&

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

&&

$$

Near Term...Farrar
Short Term...CB
Long Term...CB
Aviation...Farrar/CB
Marine...Farrar/CB
Climate...CB