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000 
FXUS61 KALY 240519
AFDALY

Area Forecast Discussion
National Weather Service Albany NY
1219 AM EST Fri Feb 24 2017

.SYNOPSIS...
Mild conditions with well above normal temperatures will persist 
into Saturday. A weak cold front will cross the region this evening 
bringing a few showers. The front will stall across the southern 
part of the region tonight, before lifting back northward as a warm 
front on Friday. There will be increasing chances for heavy rainfall 
associated with a strong cold front passage late Saturday into 
Saturday night. Gusty winds are possible along the cold front and on 
Sunday as much colder air rushes in.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
Flood Watch in effect for the western Mohawk Valley, the upper 
Hudson, the southern Adirondacks, Lake George Saratoga region and 
southern Vermont from Friday night through Sunday.
See Hydrology section for details...

As of 940 PM EST, small clusters of showers and thunderstorms
have developed across portions of NE PA and are heading NE.
Regional 00Z/24 upper air soundings indicate fairly steep mid
level lapse rates across the northeast and mid Atlantic states,
generally in the 7-7.5 C/km. An area of low level convergence
across eastern PA is expected to expand into the mid Hudson
Valley and NW CT through midnight. Expect current showers and
isolated thunderstorms to expand into this region during this
time, and may persist until shortly after midnight. A few heavy
downpours, and occasional lightning will be possible, esp closer
to I-84.

Elsewhere, little in the way of showers is expected through at
least 2 AM. There is a very weak cold front approaching the
western Adirondacks, but weakening with the main forcing lifting
well north of the region. Other than some clouds, this front
should remain dry. However, closer to daybreak, as deeper
moisture pooling to the south across PA begins to expand
northeast with a slightly strengthening low level jet segment,
showers and isolated thunderstorms are expected to develop,
mainly areas near and south of I-90 initially, before lifting
northward thereafter.

Meanwhile, pockets of clearing and light winds have allowed 
some areas of decoupling to take place, where temps have dropped
into the upper 30s to lower 40s, while remaining in the 50s
where mid level clouds are present. Expect widely varying
temperatures through the overnight hours, with some areas
possibly dipping into the mid/upper 30s where clearing persists
long enough, while other areas hover in the 40s to around 50.
Temps may actually stratify across the region and rise before
daybreak as clouds thicken across the region.

Some fog is expected to develop in areas where clearing occurs
this evening, given a moistening boundary layer along with some
cooling.

Otherwise, the warmest February day on record occurred today 
for our official climate sites of Albany and Glens Falls. Albany
reached 69 degrees, which broke the old all-time February 
record of 68 set back in 1997 on February 22nd. Glens Falls 
reached 68 degrees, which broke the all-time February record of 
65 set back in 1981 on February 21st. A daily record high of 68 
degrees was set at Poughkeepsie today, breaking the old daily 
record of 66 set in 1985.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY NIGHT/...
The aforementioned stalled frontal boundary is expected to quickly 
lift northward as a warm front Friday morning into the afternoon. 
Showers and even a few rumbles of thunder possible along and north 
of the front as it progresses northward. Best likelihood of 
measurable rainfall will be for areas north of I-90. Chances for 
showers will decrease Friday afternoon in wake of the warm front 
passage, with temperatures rising back into the lower 60s from 
Albany southward where breaks of sunshine are expected in the 
afternoon. Farther north temps should hold in the 50s, where the 
front will not pass through until later and clouds/showers will 
linger longer as well. Albany may approach another daily record max 
temp Friday. We are forecasting a high of 63, and the record is 65 
set back in 1985.

Very mild temperatures will persist Friday night, as the pattern 
amplifies with ridging along the east coast and a deepening upper 
level trough in the Midwest. A 990mb cyclone is expected to track NE 
through Lake Huron/Georgian bay area by sunrise Saturday, with the 
system's cold front approaching western New York. 

Saturday afternoon/evening expected to be an active period with a 
potential for multiple hazards, including flooding, thunderstorms, 
and strong winds as the system's cold front pushes eastward across 
the region. 

Temperatures expected to warm considerably ahead of the front by 
Saturday afternoon, with widespread upper 50s to lower 60s forecast 
for highs. Should more sunshine occur along with a slower 
progression of the cold front, it could be even warmer. For now, we 
are forecasting lower 60s for highs in the Hudson Valley and upper 
50s elsewhere.

The main active period should be from around mid to late afternoon 
into the evening as the cold front pushes through. Will mention a 
chance for thunder as there could be multiple narrow convective rain 
bands embedded in the rain shield due to strong forcing, anomalously 
high moisture, and elevated instability. Forecast mid level lapse 
rates could exceed 6.5C/km which would be very impressive for late 
February. With a 50+ kt low level jet overhead, low-topped 
convective rain bands could mix down these strong winds. Will 
continue to mention the potential in the HWO. Flooding concerns will 
also increase due to the heavy rain combined with snow melt, 
especially for areas north of the Capital District where a Flood 
Watch has been issued. See Hydrology section for more details.

Temperatures will cool behind the cold front Saturday night, with 
steady rain ending by late evening. As colder air rushes in aloft, 
some lake effect snow is expected to develop downwind of Lake 
Ontario into the western Adirondacks. At this time light 
accumulations are expected. Strong winds will also be possible 
behind the front due to strong isallobaric component and cold 
advection increasing mixing potential.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
Cold advection behind the cold front is expected Sunday with some 
lake effect snow bands possible extending east into the western 
Mohawk Valley and southern Adirondacks. Highs Sunday in the lower to 
mid 40s but lower to mid 30s northern areas.

A series of quick weak upper disturbances track through our region 
Monday through Sunday.  The quick zonal flow will allow boundary 
layer temperatures to warm but the timing, moisture and strength of 
each system is highly uncertain as there is a lot of spread in long 
range guidance and ensembles.  

In general, unsettled weather with potentially more clouds than sun 
and some chances for rain and snow showers during the days and snow 
showers at night.  A stronger piece of upper energy tracks through 
our region around Wednesday and Wednesday night with likely showers. 
Some lingering showers possible into Thursday.

Will have to wait until later this weekend and into the beginning of 
next week to be more specific about when we will have chances for 
showers and snow showers.  Still, zonal uper flow suggests no really 
cold air over our region with temperatures a bit above normal 
through the period.

Highs Monday in the 40s but some mid 30s northern areas.  Highs 
Tuesday a few degrees warmer with mainly mid to upper 40s but near 
50 southern areas and around 40 northern areas.  Warmer ahead of the 
stronger system Wednesday with highs in the lower to mid 50s but mid 
to upper 40s northern areas.  Thursday could be post cold frontal 
with cooler temperatures in the lower to mid 40s but lower to mid 
30s northern areas.

&&

.AVIATION /05Z FRIDAY THROUGH TUESDAY/...
VFR conditions will give way to MVFR conditions overnight with
some IFR conditions expected at KGFL and KPSF. Indicating MVFR 
conditions after 08Z-10Z. Increasing low level moisture and 
light winds could help low clouds and fog form around KPOU as 
well. Visibilities will slowly improve through Friday morning as
a frontal boundary slowly drifts back north. By 14Z-16Z 
visibilities will improve to VFR but ceilings may improve to VFR
only at KALB and KPOU. Friday evening there will be a return to
MVFR conditions as low level moisture increases once again.

Light and variable to calm winds overnight will become south at
5-10 KT Friday and continue into Friday evening. The winds at
KGFL and KPOU will become light and variable again Friday
evening.

Outlook...

Friday Night: Low Operational Impact. Slight Chance of SHRA.
Saturday: High Operational Impact. Breezy Definite SHRA...RA...TSRA.
Saturday Night: High Operational Impact. Breezy Likely SHRA...SHSN.
Sunday: No Operational Impact. NO SIG WX.
Sunday Night: No Operational Impact. NO SIG WX.
Monday: Low Operational Impact. Slight Chance of SHRA...SHSN.
Monday Night: Low Operational Impact. Slight Chance of SHRA...SHSN.
Tuesday: Moderate Operational Impact. Chance of SHRA...SHSN.

&&

.HYDROLOGY...
Flood Watch in effect for the western Mohawk Valley, the upper 
Hudson, the southern Adirondacks, Lake George Saratoga region and 
southern Vermont from Friday night through Sunday. Runoff will 
result from a combination of snow melt over the next couple days and 
heavy rainfall Saturday afternoon/evening.

At this time minor flooding of some main stem rivers is expected, 
including the upper Mohawk, smaller rivers/streams in areas with 
significant snow depth in the southern Adirondacks and southern 
Green Mountains of Vermont, and possibly even portions of the upper 
Hudson basin. There remains the potential for flooding for areas 
south of the watch, but confidence is much lower. So will continue 
to mention the threat in the HWO for possible expansion of the watch 
if conditions warrant. 

A warm and increasingly moist air mass will be in place through 
Saturday evening. Showers with mainly light QPF possible this 
evening into Friday. This will cause gradual snow melt and 
subsequent runoff. Then a quick-moving, strong storm system is 
expected to bring a period of moderate to heavy rainfall Saturday 
afternoon and evening. Total QPF forecast of 0.50 to around 1.50 
inches is forecast through Saturday night, with the lowest amounts 
in the Mid- Hudson Valley and Northwest Connecticut, and the highest 
amounts over the western/southern Adirondacks. The time frame for 
greatest potential for flooding is during and after the cold front 
passage due to heavy rain/snow melt combination and subsequent runoff.

Drier and colder air will filter in behind the cold front for 
Sunday, with some lake effect snow possible across the western 
Adirondacks.

For details on specific area rivers and lakes, including 
observed and forecast river stages and lake elevations, please 
visit the Advanced Hydrologic Prediction Service /AHPS/ graphs 
on our website.

&&

.CLIMATE...
All-time February high temperature records set today at Albany and 
Glens Falls. 

Albany reached 69 degrees, which broke the old all-time February 
record of 68 set back in 1997 on February 22nd. Glens Falls reached 
68 degrees, which broke the all-time February record of 65 set back 
in 1981 on February 21st. 

A daily record high of 68 degrees was set at Poughkeepsie today, 
breaking the old daily record of 66 set in 1985.

&&

.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...Flood Watch from this evening through Sunday evening for 
     NYZ032-033-038>043-082>084.
MA...None.
VT...Flood Watch from this evening through Sunday evening for 
     VTZ013>015.

&&

$$
SYNOPSIS...Thompson/JPV
NEAR TERM...KL/JPV
SHORT TERM...JPV

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