871
FXUS61 KALY 170600
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
200 AM EDT Mon Jun 17 2024

.SYNOPSIS...
High pressure shifts east of New England tonight. Hot and humid
weather arrives Monday and continues through most of the week
with isolated to widely scattered showers and thunderstorms
possible from midweek onward. Dangerous heat and humidity levels
will impact many valley areas Tuesday through Thursday.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
.UPDATE...As of 0145 AM EDT, With largely clear skies outside of
scattered high cirrus, efficient radiative cooling in sheltered
areas across the southern Adirondacks, Upper Hudson Valley, and
eastern Catskills has allowed temperatures to fall fairly
rapidly into the upper 40s to mid 50s, while temperatures remain
in the upper 50s to mid 60s elsewhere where a southerly to
southeasterly breeze has stymied cooling. An increasing breeze
through the remainder of the night in response to surface high
pressure sliding farther east and increasing high clouds will
limit additional cooling, with temperatures bottoming out at
lows in the upper 40s to near 60 degrees across the region.
Chances for patchy radiation fog are decreasing as clouds and
winds increase as well. As such, forecast remains on track; see
previous discussion below...

.Previous...A 1025 hPa sfc anticyclone shifts east to southeast
of New England this evening into tonight. Low and mid level
heights will continue to rise tonight with strong ridging
building in from the Mid Atlantic Corridor and the Southeast. A
sfc warm front will approach from the Ohio Valley and the Mid
Atlantic States. Mid and high clouds will increase. There is a
small chance some lower stratus moves in south and east of
Capital Region. Some cooling will occur with the sct-bkn mid and
high clouds with light to calm winds.

Lows will be in the 50s to around 60F with some pockets of upper
40s possible in the sheltered valleys.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY NIGHT/...
Heat Advisories issued noon Tuesday to 8 pm Thursday for all
of southern VT, and eastern NY excluding most of the southern
Adirondacks, and the eastern Catskills...

Tomorrow will be the transition to the heat and humidity, as the
warm front lifts north and east of the region. Low and mid level
warm advection continues. The latest NAEFS shows H500/H700
height anomalies of +2 to +3 STD Devs above normal. A few
showers or thunderstorms may pop up over the southern
Adirondacks with the warm front and weak mid level impulse. Sfc
dewpoints rise into the low to mid 60s with some upper 50s over
the higher terrain, as humidity levels increase. Max temps were
accepted close the latest EC/GFS MOS blend with mid and upper
80s in the valleys with a few isolated 90F readings, and mid 70s
to lower 80s over the higher terrain. Heat indices stay below
advisory thresholds of 95F or less.

Monday night will be muggier and much more humid compared to
past few night, as the ride strengthens aloft. The skies will be
mostly clear to partly cloudy. Lows will be in the mid to upper
60s in the valley areas, and upper 50s to mid 60s over the
hills and mountains.

Tuesday into the mid week the heat and humidity levels ramp up.
H850 temps on the latest GFS/ECMWF increase to +18C to +21C. The
H850 temp anomalies are +1 to +3 STDEVs above normal. Southerly
winds of 5 to 15 mph will allow dewpoints to creep up in the 60s
to near 70F. Heat indices in the Hudson River Valley, Mohawk
Valley and CT River valleys rise into the mid 90s to lower 100s.
Extensive collaboration with neighboring WFOs was to go with
Heat Advisories TUE and extend through THU with possible
upgrades to Excessive Heat Warnings for certain areas WED and
THU. Record maxes could be achieved in some locations (see the
Climo section below). Any isolated thunderstorms threat should
be confined to the Adirondack Park/western Mohawk Valley with a
capped atmosphere. The differential heating between the terrain
could allow for a pop-up convective cell or two. Max temps were
from an ECM Ensemble MOS/NBM blend with lower and mid 90s below
1000 ft in elevations and mid 80s to near 90F over the hills
towns and mtns.

A balmy and muggy night will occur Tue night with mid 60s to
lower 70s for low temps with the ridge along the East Coast
firmly in place. It will be mostly clear overnight.

Wednesday should be one of the peak hot days of the heat with
596-597 decameter heights over NY and New England. We may have
to upgrade portions of the Capital District, Mohawk Valley,
Upper Hudson River Valley, Lake George Region and the CT River
Valley of southern VT to an Excessive Heat Warnings with heat
indices hovering near 105F. Dangerous hot and humid weather will
continue over much of the region where the advisories are out.
We may have to add in Litchfield Co including the hills to the
advisories and portions of the Berkshires if heat indices hit
100F or so, or it is the 2nd day of 95-99F. The NBM numbers look
a little warm with H850 temps are around 20C. We could see some
upper 90s, but local wind effects may be needed. We have highs
in the upper 90s (97-98F in the immediate Capital District, the
CT River Valley and portions of the Hudson River Valley). The
higher terrain will be the mid 80s to lower 90s. Most the lower
elevations will be in the 90s.  We could see some isolated
thunderstorms pop- up north and west of the Capital District. It
will be important to stay cool and hydrated if outside on
Wednesday.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Heat Advisories continue until 8 pm Thursday for all of
southern VT, and eastern NY excluding most of the southern
Adirondacks, and the eastern Catskills...

Heat will continue a bit longer into the long term period with
a strong 500 hPa upper high centered over the mid-Atlantic
peaking around 598 dm (+2 to +3 STDEV). Thursday looks to be the
hotter day of the period before the high slowly shifts
southward and weakens Friday into the weekend. 850 hPa
temperatures Thursday afternoon look to be around +20C. Even
accounting for some superadiabatic mixing, highs may reach the
mid to upper 90s in the valleys with upper 80s to lower 90s
across the higher elevations. While some localized valley areas
could approach 100 degrees, there was not enough confidence to
forecast a temperature that high at this time. Dewpoints in the
mid to upper 60s to lower 70s should result in widespread heat
index values (feels like temperatures) in the upper 90s to lower
100s in the valleys with some upper 80s to localized mid-90s
across higher elevations. A Heat Advisory has been issued for
some valley areas through the day Thursday. An upgrade to an
Excessive Heat Warning may be needed for some areas if
confidence on heat indices of 105 F or greater increases. Little
relief will be in place Wednesday and Thursday nights with lows
in the mid-60s to lower 70s.

The combination of differential heating plus the potential for some
weak upper level energy to track over the northern periphery of the
ridge and an approaching front near the US/Canadian border could
lead to some isolated showers and thunderstorms Thursday afternoon,
especially for far northern areas. The southern shift in the high,
additional upper-level shortwave energy and the frontal boundary
dropping southward should result in a gradual downward trend in
temperatures Friday through the weekend along with daily chances for
showers and thunderstorms. Though, heat indices may still reach the
mid to upper 90s across some valley areas on Friday and trends will
be monitored for any additional heat headlines.

&&

.AVIATION /06Z MONDAY THROUGH FRIDAY/...
VFR conditions expected to prevail for the majority of the time
through 06 UTC Tuesday. The only exception is perhaps a small window
starting at 08-09 to 11 UTC when MVFR ceilings may develop at PSF
and POU thanks to southeasterly winds advecting marine moisture
inland. While we have been monitoring the dew point depression at
GFL overnight since the temperature and dew point are quite close,
the expansive cirrus deck should limit radiational cooling so we
held off on including fog and MVFR flying conditions. Will continue
monitoring satellite trends and adjust as need as we approach the
pre-dawns.

Any early fog/lower cigs will burn off by 13-14 UTC with VFR
conditions continuing thereafter. Expecting the blank of cirrus
clouds to dissipate by 17-19 UTC resulting in clearing skies.

Southeast winds remain breezy at ALB overnight sustained around 5-
10kts with occasional gusts to 15-17kts with lighter winds at or
less than 5kts at PSF, POU and GFL. Southerly winds increase at all
terminals by 13-14 UTC becoming sustained 5-10kts with gusts up to
15kts. Winds turn light and variable by 02-03 UTC/18 at all
terminals.

Outlook...

Monday Night to Thu night: No Operational Impact. NO SIG WX.
Friday: Low Operational Impact. Slight Chance of SHRA...TSRA.

&&

.CLIMATE...
Record High Temperatures:

Tuesday June 18:
Albany - 97 (1957, 2018)
Glens Falls - 95 (1907)
Poughkeepsie - 94 (2018)

Wednesday June 19:
Albany - 94 (1995)
Glens Falls - 97 (1995)
Poughkeepsie - 92 (1941, 1943, 1993, 2016)

Thursday June 20:
Albany - 97 (1953)
Glens Falls - 97 (1923)
Poughkeepsie - 96 (2012)

Friday June 21:
Albany - 97 (1938)
Glens Falls - 96 (2012)
Poughkeepsie - 97 (1949)

&&

.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...Heat Advisory from noon Tuesday to 8 PM EDT Thursday for
     NYZ038>043-047>054-059>061-064>066-083-084.
MA...None.
VT...Heat Advisory from noon Tuesday to 8 PM EDT Thursday for
     VTZ013>015.

&&

$$

SYNOPSIS...Wasula
NEAR TERM...Main/Picard/Wasula
SHORT TERM...Wasula
LONG TERM...Rathbun
AVIATION...Speciale
CLIMATE...Rathbun