630
FXUS61 KALY 131102
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
702 AM EDT Mon May 13 2024

.SYNOPSIS...
Morning sun mixes with increasing clouds as temperatures
turn warmer ahead of a warm front. Chances for showers and some
storms increase this afternoon into this evening before we trend
drier overnight into Tuesday. Temperatures become even warmer
tomorrow ahead of a weak cold front and upper level disturbance
which will lead to more widespread showers and potentially a
few storms Tuesday afternoon through Wednesday. Then, drier and
seasonably warm conditions return late week.

&&

.NEAR TERM /THROUGH TONIGHT/...

As of 6:55am, we issued a Special Weather Statement through 9am
given areas of dense fog early this morning in the immediate Capital
District into parts of Greene, Dutchess, Columbia, Litchfield
and Berkshire County. Probabilistic guidance based on GOES16
satellite data shows regions of reduced visibilities in these
areas which increased confidence that fog was dense enough to
warrant a Special Weather Statement (SPS). Forecast soundings
show fog burning off by 9am so the SPS will expire by that
time. Otherwise, it is chilly start to our Monday with many
starting the day off in the low to mid 40s thanks to favorable
radiational cooling overnight.

Previous discussion...Early patchy fog quickly burns off by
8-9am giving way to mainly sunny skies thanks to upper level
ridging/subsidence in place this morning. Initially cool
temperatures in the 40s will warm- up rather rather quickly
today in response to the strong May sun angle and deep boundary
mixing within the rather dry column ahead of an approaching warm
front. Forecast soundings show boundary layer mixing extending
up to 850hPa and with increased warm air advection aloft
ushering in 8C to 9C isotherms, we leaned on the warmer end of
the ensemble guidance for high temperatures today showing the
Mohawk and Hudson valley areas reaching into the low 70s with
the hill towns and higher terrain reaching into the mid to upper
60s.

Mid and upper level moisture along the leading edge of the warm
air sector spill overtop upper level ridging this afternoon
resulting in sun fading behind increasing clouds. Chances for
showers also increase this afternoon by 18 - 21 UTC into this
evening, mainly for areas along and north of I-90, where the
highest moisture and forcing will line-up along the periphery of
the upper level ridging. With PWATs exceeding one inch within
the incoming warm sector, some elevated convection is also
possible late this afternoon into this evening, again mainly
for areas along and north of I-90.

Ridging strengthens tonight in response to a shortwave trough
approaching from the Midwest. This should steer scattered
showers and thunderstorms northward into the North Country by 03
to 06 UTC and trend POPs downwards by this time to message a
dry trend. Clouds will also lift northward allowing for clearing
skies, especially from the Capital District southward into the
mid- Hudson Valley and NW CT. Despite the clearing sky trend, we
remain in the warm sector so temperatures will stay mild and
dew points elevated which will make it feel slightly humid.
Overnight lows only expected to drop into the low to mid 50s.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
Dry weather continues into Tuesday morning as we remain under
the influence of a weak sfc high positioned off the coast and
upper level ridging. Eastern NY and western New England will
also be within the warm sector (850hPa isotherm +10C to +11C) ahead
of a weak/diffuse boundary in southern Ontario that will slowly
slide southeastward. Clouds will be on the increase Tuesday
afternoon as the aforementioned shortwave trough from the
Midwest tracks into the Ohio Valley and moisture spills
eastward. Despite the increasing clouds, deep boundary layer
mixing within the warm sector ahead of the boundary will help
temperatures rising well into mid to upper 70s. We leaned on the
warmer end of guidance once again and would not be surprised if
some sites reach 80F as southerly winds become a bit breezy
sustained 8-15mph. Dew points will also be on the rise rising
well into the 50s towards 60 so the increased humidity will make
it feel even warmer.

Some showers and thunderstorms developing ahead of the weak
boundary will be approaching from Central NY and the North
Country Tuesday afternoon but the better forcing remains north
and west of the Capital District. We thus limited likely POPs
to the southern/western Adirondacks, Mohawk Valley and northern
Catskills areas with just chance POPs from Albany south and
eastward into western New England. With PWATs over 1", any
thunderstorms will be capable of producing periods of steady
rainfall. Areas in the mid-Hudson Valley and NW CT should
remain mainly dry most of Tuesday as they remain displaced from
the better forcing/moisture.

The better potential for increased shower coverage and isolated
thunderstorms occurs Tuesday night into Wednesday as the upper
level trough/weak closed low from the Ohio Valley slides
eastward resulting in increased height falls. The boundary from
southern Ontario washes out as it pushes into areas mainly north
and west of Albany on Wednesday but should still provide a
localized convergence zone and focus for scattered showers and
isolated thunderstorms. With PWATs remaining over 1" and dew
points near 60, some steadier periods of rain are still
possible; however, overall thunderstorm potential appears
limited on Wednesday given mainly cloudy skies and southeasterly
to easterly sfc winds. Since overall forcing for ascent on
Wednesday is rather broad and weaker, we capped POPs at likely
and removed categorical mention since there likely will be
periods of dry time.

Temperatures stay mild Tuesday night given cloudy skies and the
muggy/mild air mass so overnight lows will likely only drop into
the mid to upper 50s. Cloudy skies and southeasterly winds on
Wednesday will keep temperatures relatively cooler with many
only reaching into the mid to upper 60s; however, it will still
feel muggy with dew points in the 50s to near 60.

The upper level closed low slowly exits to our east late Wednesday
afternoon into Wednesday night with upper level ridging and
subsidence building in its wake. This will yield a drying trend
Wednesday night with partial clearing skies. Overnight lows
drop into the low to mid 50s.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
The extended forecast period is generally progged to begin dry as
modest height rises precede the eastward building of a weak surface
high from the Ohio Valley. Of course, with a coastal low slowly
pushing east away from the Mid-Atlantic Coast, much of eastern New
York and western New England will remain under northeast, cyclonic
flow which could allow some light, scattered showers to take place
Thursday morning. This will be especially true for higher terrain
areas east of the Hudson (Southern Greens, Berkshires and Taconics)
where upslope enhancement could play a factor in overcoming the fast-
advancing, mid-level dry air. The aforementioned low will continue
to push east away from the coastline throughout the day Thursday
with high pressure sliding in at the surface and modest ridging
building aloft. Dry conditions are, therefore, expected to continue
through at least the first half of Friday as high pressure keeps
hold of the region despite its swift track eastward.

The forecast for the latter half of the extended period retains a
fair amount of uncertainty as medium to long range models show
discontinuities in their evolution of an upper-level trough and
associated surface low that holds our next chance for widespread
rain. Currently, the GFS and CMC-NH show the most consistency
with one another, depicting the system as a negatively-tilted,
northern- stream, open wave sliding across portions of the upper
Midwest, Ohio Valley and Great Lakes with an attendant low
tracking through the Great Lakes at the surface. With this
solution, widespread rain looks to begin late Friday
afternoon/early Saturday evening and last through Saturday
afternoon/evening before tapering off to mere showers by
Saturday night and ceasing completely by early Sunday morning.
While the ECMWF depiction of this system is similar, more
substantial timing discrepancies exist in the eastward shift of
the aforementioned coastal low which would limit the dry period
Thursday into Friday. Additionally, discrepancies in the track
of the main low associated with this system, shown in all three
models, increases uncertainty in the extent of widespread rain
Friday through Saturday. Will continue to monitor conditions
over the coming days as guidance comes into greater agreement.

Despite discontinuities regarding Friday and Saturday`s forecast,
guidance consistently paints Sunday as a dry day as an amplified
ridge and high pressure system build into the region and across much
of the East Coast. High temperatures throughout the extended period
generally look to remain within the 60s and 70s across the region
with lows in the 40s and 50s.

&&

.AVIATION /12Z MONDAY THROUGH FRIDAY/...
Through 06z Tuesday...VFR conditions currently prevail at all
terminals with clear skies across much of Eastern New York and
western New England. However, with wet surface conditions and
high, low-level relative humidity, it is expected that some fog
could develop at the terminals this morning. Latest METAR obs
indicate the highest relative humidity at KGFL and KPSF thus
far, but the GOES-16 night fog product shows some valley fog
developing within the vicinity of not just these terminals, but
KPOU as well. Therefore, with the expectation for skies to
remain clear, yielding prime radiational cooling conditions,
included TEMPOs for fog at all terminals this morning. KGFL and
KPSF are expected to have the greatest reduction to visibility
given the latest trends, but KPOU could also cross into the
MVFR to possibly the IFR category given its fairly wet soils.
KALB also has a TEMPO for possible impacts due to fog, but
confidence is on the lower side for this terminal, so maintained
high MVFR-category conditions for now.

Any fog that develops early this morning should quickly burn off
come sunrise, yielding VFR conditions once again. Throughout the
remainder of the 06z period, clouds are anticipated to go on an
increasing trend at each terminal as an upper-level disturbance
crosses the region. Additionally, the approach of a warm front
later in the period will result in the increased chances for
showers. VFR conditions should remain in place through at least
23-01z when ceilings could lower and visibility could be reduced
due to some scattered showers. Confidence is lower in the
progged conditions towards the end of the period as showers
should be rather scattered in nature, but it is certainly
possible that any showers to grace each terminal could worsen
conditions to the MVFR category. Will continue to provide
increasing detail in later updates.

Winds throughout the period will prevail primarily out of a
southerly direction at sustained speeds of 4-8 kt. It is
possible, however, for KALB and KPSF to have some gusts of about
15-20 kt later in the period with the approach and subsequent passing
of the front.

Outlook...

Tuesday Night: High Operational Impact. Likely SHRA...TSRA.
Wednesday: High Operational Impact. Likely SHRA...TSRA.
Wednesday Night: Moderate Operational Impact. Chance of SHRA...TSRA.
Thursday: Low Operational Impact. Slight Chance of SHRA.
Thursday Night: No Operational Impact. NO SIG WX.
Friday: Low Operational Impact. Slight Chance of SHRA.
Friday Night: Moderate Operational Impact. Chance of SHRA.
Saturday: Moderate Operational Impact. Chance of SHRA.

&&

.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
MA...None.
VT...None.

&&

$$

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