363
FXUS61 KALY 202000
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
400 PM EDT Thu Jun 20 2024

.SYNOPSIS...
Hot and muggy weather will continue through the evening
hours, with showers and thunderstorms possible.  Some storms will be
severe and capable of producing damaging winds, hail and heavy
downpours.  While it will remain warm and humid on Friday, it won`t
be quite as hot as the past few days, with some additional showers
and thunderstorms possible, especially for southern areas. Continued
warm and sticky weather will continue into the weekend, with some
additional showers and thunderstorms possible each day, mainly in
the afternoon and evening hours.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
As of 400 PM EDT...Severe Thunderstorm Watch #438 is in effect
for northern areas (Herkimer, Hamilton, Fulton, Warren, Saratoga
and Washington Counties in eastern New York and Bennington and
Windham Counties in southern Vermont) through 8 PM this evening.
The threat for damaging winds is the main threat, but hail and
heavy downpours will be possible as well.

Strong upper level ridge (around 597 dm) is centered just south
of the region over the mid Atlantic States. This ridge has been
slowly drifting southward and our area is on the northern fringe
of the strongest ridging, allowing for weak disturbances to
rotate around the northern edge. The heights and warm temps
aloft have allowed for very warm temps again today, with valley
areas reaching the lower to middle 90s. With dewpoints in the
lower 70s, heat index values have reached around 100 degrees,
which is firmly in Heat Advisory criteria. Heat Advisories
remain in effect through 8 pm this evening for the entire area
and today`s temps/heat index values look to be the highest of
this recent heat wave.

SPC mesoanalysis shows very impressive MLCAPE of 2000-3000 J/kg
in place over the region thanks to the very warm and muggy air
mass in place. Low level lapse rates are very steep due to the
strong heating, with values in the 7-8 C/km range, while mid
level lapse rates are weaker due to the warm temps aloft
(generally around 5.5 to 6 C/km). The best 0-6 km bulk shear
remains well north and west of the region.

Thanks to an MCV sliding by to the north, loosely organized
convection has been congealing into clusters across the
Adirondacks and Lake George area. Some additional convection
(mainly isolated) has developed over parts of western New
England, while another another broken line of weaker convection
is moving across central New York. Based on the latest CAMs and
the latest mesoanalysis, northern areas will have the greatest
threat for more organized and stronger storms over the next few
hours, although some isolated cells are possible within the
pulse environment across the rest of the area. Even within the
isolated cells, locally damaging winds are possible due to
precip loading/wet microbursts thanks to the high PWATs in
place. The high PWATs, high freezing levels and effective cloud
processes could lead to some high rainfall rates, with hourly
rates over 1.50" per hour possible within the heaviest cells.
The recent dry weather should help prevent a widespread flash
flood threat, but can`t rule out some isolated issues,
especially if storms pass slowly across any urbanized areas or
backbuild over the small areas, such as what has occurred across
parts of far southeastern Vermont this afternoon.

While the northern areas should see activity exiting by earlier
in the evening, the additional convection over CNY should be
passing across central parts of the area, including the Capital
Region, through about 8 or 9 PM this evening. The threat for
strong convection with this activity looks more isolated
compared to the storms passing through northern areas earlier,
but can`t rule out some rogue gusty winds or heavy downpours.
Afterward, activity should mainly be done, allowing for quieter
weather through the rest of the overnight hours. Some lingering
clouds are expected, although it will remain very muggy. Any
areas that saw rain will be susceptible to the development of
patchy fog. Otherwise, it will be partly cloudy and mild with
lows in the mid 60s to lower 70s.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
On Friday, the strong ridging will continue to shift further
south and west, becoming centered over the Tennessee Valley.
Our area will continue to be on the northern fringe of this
ridging and closer to the zonal flow to the north. A weak
boundary to the north and west will be dropping southward across
the region on Friday. During daytime heating, some additional
showers and thunderstorms will develop during the afternoon and
evening hours, especially for southern parts of the area.
Overall, lapse rates don`t look as impressive as Thursday and
shear is still fairly weak. A few strong storms will gusty winds
can`t be ruled out for southern areas, but the threat for severe
weather looks more isolated. Once again, high PWATs could lead
to heavy downpours again on Friday, so can`t rule out some
ponding of water or an isolated flash flood. Temps look a little
cooler for most areas compared to Thursday, with 80s to near 90
for most spots. However, the mid Hudson Valley and NW CT may
still reach the lower 90s, so will allow for the Heat Advisory
to continue for those areas through the evening hours.

Showers and thunderstorms should diminish on Friday evening with
the loss of daytime heating. As a result, mainly dry weather is
expected on Friday night with a partly cloudy sky and some
patchy fog.  It will still be mild and muggy with lows still in
the upper 60s to low 70s.

The boundary will be draped across the area on Saturday. This
should allow for more cloud cover, although the front may be
gradually drifting back northward as a warm front at some point
during the day Saturday into Saturday night. Some more showers
and thunderstorms are possible, but activity looks scattered and
the best coverage will be during the afternoon and evening
hours. The severe threat looks fairly low on Saturday, but
again, can`t rule out any downpours leading to ponding of water.
Highs will generally be in the 80s and heat index values should
stay under Heat Advisory criteria. Will keep a chance for
showers or t-storms into Sat night with lows in the upper 60s,
along with continued muggy conditions.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
Continued warm and humid conditions are expected to be in place
at the start of the long term period on Sunday. Valley areas
will be reaching into the upper 80s to low 90s once again, and
some heat index values could be approaching advisory criteria in
a few southern areas again. As a frontal boundary approaches
from the west, another round of showers and t-storms look to
occur during the afternoon and evening hours. With the expected
warm and humid conditions, there should be enough instability in
place, so will need to watch the threat for some stronger storms
once again as well. There are some timing differences in the
guidance regarding when the front moves through the area, as it
could be crossing on Sunday night or even early Monday, but
there should be enough forcing for an organized line or cluster
of storms on Sunday.

Will keep POPs in the chance range for Sunday night into Monday,
as the front and associated trough moves across the region. Once
the front clears the area, less humid air will be moving towards
the area, although this will be a fairly subtle change and temps
will still be above normal. By late Monday, skies will be
clearing out as well and the threat for precip will be lowering
as well.  Will still keep temps well into the 80s for Monday.

Quieter weather is expected for Tuesday with high pressure
nearby. While it should be rain-free, temps will still be rather
warm (valley areas in the mid to upper 80s) and it will be
fairly humid (dewpoints into the 60s) as well.

The next system will impact the region around Wednesday with
another round of showers and thunderstorms. In addition, temps
will be fairly warm once again with humid conditions. More
significant cooling and drying is expected towards Thursday
behind this system.

&&

.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
Through 18z Friday...VFR conditions currently prevail across all
TAF sites this afternoon as adjacent high pressure keeps hold
over the region. An approaching disturbance has allowed a few
pop-up thunderstorms to develop outside of terminal vicinities
(in the Southwest Adirondacks) as of this update with the
expectation that additional isolated to scattered storms will
develop across the area throughout the afternoon.

Have included TEMPO groups at KALB/KGFL/KPSF for a couple of
hours this afternoon to account for the possibility of storms
crossing over terminal bounds. While latest CAMs have struggled
to depict the ongoing convection, there is moderate confidence
in pop-up storms impacting these terminals mainly between 20z
this afternoon and 02z this evening. This will especially be
true at KGFL where thunderstorms are more likely. IFR conditions
are anticipated with thunderstorms due to reduced visibility
from heavy downpours. Strong wind gusts and small hail are also
possible.

Upon convection ending shortly after sunset due to the loss of
daytime heating, VFR conditions will be returned to
KALB/KGFL/KPSF with such conditions remaining steady at KPOU.
However, muggy conditions overnight, especially if KGFL and KPSF
receive rain this afternoon/evening, will likely lead to fog
development. MVFR to IFR conditions are definitely possible at
KGFL and KPSF, however we did add BCFG at KALB for a couple of
hours between 10-12z since model soundings are showing slower
winds and increased surface humidity at that time. But this is
also dependent on whether or not the vicinity receives rain to
increase low-level humidity. Nonetheless, VFR conditions will
then be returned to at all sites after 12z.

Winds throughout the period will generally be light out of the
southwest to start and becoming northeasterly by the end of the
period. Sustained speeds will reach 3-6 kt. However, should a
stronger thunderstorm cross over one of the terminals, brief
strong gusts are possible.

Outlook...

Friday Night: Moderate Operational Impact. Chance of SHRA...TSRA.
Saturday: High Operational Impact. Likely SHRA...TSRA.
Saturday Night: Moderate Operational Impact. Chance of SHRA...TSRA.
Sunday: High Operational Impact. Likely SHRA...TSRA.
Sunday Night: High Operational Impact. Likely SHRA...TSRA.
Monday: Moderate Operational Impact. Chance of SHRA...TSRA.
Monday Night: No Operational Impact. NO SIG WX.
Tuesday: No Operational Impact. NO SIG WX.

&&

.ALY WATCHES/WARNINGS/ADVISORIES...
CT...Heat Advisory until 8 PM EDT this evening for CTZ001.
     Heat Advisory until 8 PM EDT Friday for CTZ013.
NY...Heat Advisory until 8 PM EDT this evening for NYZ032-033-
     038>043-047>054-058>061-063-082>084.
     Heat Advisory until 8 PM EDT Friday for NYZ064>066.
MA...Heat Advisory until 8 PM EDT this evening for MAZ001-025.
VT...Heat Advisory until 8 PM EDT this evening for VTZ013>015.

&&

$$

SYNOPSIS...Frugis
NEAR TERM...Frugis
SHORT TERM...Frugis
LONG TERM...Frugis
AVIATION...Gant