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Area Forecast Discussion (AFD)

Issued by Albany, NY (ALY)

                            
000
FXUS61 KALY 252012
AFDALY

Area Forecast Discussion
National Weather Service Albany NY
412 PM EDT Fri May 25 2018

.SYNOPSIS...
High pressure building east off the Atlantic coast will bring 
very warm conditions to our region through Saturday with 
increasing amounts of humidity. Some showers or thunderstorms 
are possible over the holiday weekend as a backdoor cold front 
moves through the region.

&&

.NEAR TERM /THROUGH SATURDAY/...
A weak backdoor cold front begins to approach from the north 
through tonight and there could be an isolated shower in far 
northern areas by daybreak. Otherwise, light south winds should
persist in parts of the Hudson Valley including the Capital 
District, which could prevent temperatures from falling as much 
as they could. Other areas will trend to light or near calm 
winds. Lows mainly in the lower to mid 60s but some upper 50s 
northern areas.

On Saturday, the weak backdoor cold front drops south through 
the day but the leading edge of the convergence on the leading 
edge of the cold front should hold off until the afternoon from 
the Mohawk Valley and southern VT and points south. So, 
scattered showers and thunderstorms develop in northern areas 
around noon, then build south and east through the afternoon 
and evening. 

Instability looks to be considerable but mostly surface based 
and midlevel lapse rates are not very steep. Boundary layer 
winds weaken and mean 0-6 km bulk shear remains weak through 
the day. The low level temperature and moisture gradients along 
the front are not too extreme. Thunderstorms could be strong but
mainly look to be sub severe at this time.

There should be more sun than clouds most of the day along and
south of the Mohawk Valley and southern VT but more clouds than
sun in northern areas. Winds will be lighter but still from the
west and southwest ahead of the cold front. So, highs Saturday
again well into the 80s but mid to upper 70s northern areas.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
Weather over the holiday weekend will remain unsettled but not 
a "wash out". Saturday night, a weak cold front will become 
nearly stationary across southern New York. Surface winds will 
be southeast to south over our region but boundary layer winds
remain light south to southwest through Sunday. There is 
considerable uncertainty as to how far west the weak front 
becomes stationary, as the western Mohawk Valley, Schoharie 
Valley and eastern Catskills could be noticeably warmer and have
some breaks in the clouds, on the warm side of the front. 
Overnight lows look to range from the mid 50s to lower 60s.

Additional scattered showers are possible Sunday, with some 
isolated thunder in the western Mohawk Valley, Schoharie Valley 
and eastern Catskills. Onshore surface winds and more clouds 
than sun will result in highs Sunday in the 60s to around 70 
degrees. Scattered showers continue Sunday night with lows 
generally in the lower 50s.

Unsettled weather continues for Memorial Day. Models indicating
a surface trough moving across the region mainly during the 
afternoon hours with a northwest flow aloft. The GFS is 
indicating increasing instability, especially across the 
northwest half of the area, so will mention possible 
thunderstorms as well. There will be residual low-level moisture
with surface dewpoints in the lower 60s, so it will feel 
somewhat humid as well. Development of low-level stratus clouds 
could limit surface heating and duration may be tricky in terms 
of the temperature forecast. Until there is higher confidence in
cloud cover, will mention high temps in the lower to mid 70s 
for much of the region.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
After a weekend of unsettled weather ridging is expected to 
build in at surface and aloft dominating our weather through 
middle of the week with fair conditions and warm temperatures 
5 to 10 degrees above normal. Will have to watch for the  
possibility for low-level stratus clouds each morning otherwise 
plenty of sunshine expected.

Uncertainty in the forecast grows for the latter part of the
week as the remnants of/moisture from Alberto may get picked up
by a short wave trough and approaching low pressure system and
brought into the region so have chances for showers Thursday
night and Friday. Please refer to forecasts issued by the 
National Hurricane Center for information on Alberto. 

&&

.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
VFR conditions expected to prevail at the KALB/KPOU/KGFL/KPSF 
terminals through the 24 hour TAF period ending 18Z Saturday, 
with mainly just some passing high level cirrus clouds. SCT mid 
level clouds are expected to develop at KGFL tonight as a 
disturbance moves across far northern NY. There will be a PROB30
for thunderstorms at KGFL after 17Z. 

Winds today will be west-southwest and increasing to 10-15 kts 
with gusts around 20-25 kts becoming common during the 
afternoon as mixing potential increases. Winds speeds will 
decrease to less than 10 kts after sunset and remain between 5
and 8 kts through the end of the TAF period.

Outlook...

Saturday Night: Moderate Operational Impact. Scattered SHRA...TSRA.
Sunday: Moderate Operational Impact. Scattered SHRA.
Sunday Night: Moderate Operational Impact. Scattered SHRA.
Memorial Day: Moderate Operational Impact. Chance of SHRA...TSRA.
Monday Night:  Slight Chance of SHRA...TSRA.
Tuesday: No Operational Impact. NO SIG WX.
Tuesday Night: No Operational Impact. NO SIG WX.
Wednesday: No Operational Impact. NO SIG WX.

&&

.FIRE WEATHER...
Warm conditions, with increasing humidity, will continue 
through Saturday as high pressure builds off of the Atlantic 
coast. Some showers or thunderstorms are possible over the 
holiday weekend.

RH values recover to 70 to 90 percent. RH values drop to 30 to 
55 percent Saturday.

Gusty west to south west winds this evening will diminish to 15
mph or less tonight. West to southwest winds around 15 mph 
Saturday become southeast at 15 mph or less late Saturday 
afternoon.

&&

.HYDROLOGY...
No hydrologic issues are anticipated over the next few days.

Dry weather is expected to continue through tonight with high 
pressure in control. As a result, rivers, streams, lakes, ponds,
reservoirs, brooks, creeks and kills will remain fairly steady 
over the next few days. 

Our next chance for scattered showers and possible thunderstorms
will be over the holiday weekend. Northern and central areas 
will have the best chance of seeing a shower or thunderstorm on 
Saturday, with better chances across the remainder of the area 
for Sunday into Monday. Rainfall amounts will be highly variable
due to thunderstorm activity and some locations may stay 
completely dry.

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.

&&

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

&&

$$
SYNOPSIS...NAS
NEAR TERM...11/NAS
SHORT TERM...NAS/JPV/JVM
LONG TERM...IAA
AVIATION...11/JPV
FIRE WEATHER...NAS/JVM
HYDROLOGY...NAS/JVM

901 
FXUS61 KALY 252012
AFDALY

Area Forecast Discussion
National Weather Service Albany NY
412 PM EDT Fri May 25 2018

.SYNOPSIS...
High pressure building east off the Atlantic coast will bring 
very warm conditions to our region through Saturday with 
increasing amounts of humidity. Some showers or thunderstorms 
are possible over the holiday weekend as a backdoor cold front 
moves through the region.

&&

.NEAR TERM /THROUGH SATURDAY/...
A weak backdoor cold front begins to approach from the north 
through tonight and there could be an isolated shower in far 
northern areas by daybreak. Otherwise, light south winds should
persist in parts of the Hudson Valley including the Capital 
District, which could prevent temperatures from falling as much 
as they could. Other areas will trend to light or near calm 
winds. Lows mainly in the lower to mid 60s but some upper 50s 
northern areas.

On Saturday, the weak backdoor cold front drops south through 
the day but the leading edge of the convergence on the leading 
edge of the cold front should hold off until the afternoon from 
the Mohawk Valley and southern VT and points south. So, 
scattered showers and thunderstorms develop in northern areas 
around noon, then build south and east through the afternoon 
and evening. 

Instability looks to be considerable but mostly surface based 
and midlevel lapse rates are not very steep. Boundary layer 
winds weaken and mean 0-6 km bulk shear remains weak through 
the day. The low level temperature and moisture gradients along 
the front are not too extreme. Thunderstorms could be strong but
mainly look to be sub severe at this time.

There should be more sun than clouds most of the day along and
south of the Mohawk Valley and southern VT but more clouds than
sun in northern areas. Winds will be lighter but still from the
west and southwest ahead of the cold front. So, highs Saturday
again well into the 80s but mid to upper 70s northern areas.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
Weather over the holiday weekend will remain unsettled but not 
a "wash out". Saturday night, a weak cold front will become 
nearly stationary across southern New York. Surface winds will 
be southeast to south over our region but boundary layer winds
remain light south to southwest through Sunday. There is 
considerable uncertainty as to how far west the weak front 
becomes stationary, as the western Mohawk Valley, Schoharie 
Valley and eastern Catskills could be noticeably warmer and have
some breaks in the clouds, on the warm side of the front. 
Overnight lows look to range from the mid 50s to lower 60s.

Additional scattered showers are possible Sunday, with some 
isolated thunder in the western Mohawk Valley, Schoharie Valley 
and eastern Catskills. Onshore surface winds and more clouds 
than sun will result in highs Sunday in the 60s to around 70 
degrees. Scattered showers continue Sunday night with lows 
generally in the lower 50s.

Unsettled weather continues for Memorial Day. Models indicating
a surface trough moving across the region mainly during the 
afternoon hours with a northwest flow aloft. The GFS is 
indicating increasing instability, especially across the 
northwest half of the area, so will mention possible 
thunderstorms as well. There will be residual low-level moisture
with surface dewpoints in the lower 60s, so it will feel 
somewhat humid as well. Development of low-level stratus clouds 
could limit surface heating and duration may be tricky in terms 
of the temperature forecast. Until there is higher confidence in
cloud cover, will mention high temps in the lower to mid 70s 
for much of the region.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
After a weekend of unsettled weather ridging is expected to 
build in at surface and aloft dominating our weather through 
middle of the week with fair conditions and warm temperatures 
5 to 10 degrees above normal. Will have to watch for the  
possibility for low-level stratus clouds each morning otherwise 
plenty of sunshine expected.

Uncertainty in the forecast grows for the latter part of the
week as the remnants of/moisture from Alberto may get picked up
by a short wave trough and approaching low pressure system and
brought into the region so have chances for showers Thursday
night and Friday. Please refer to forecasts issued by the 
National Hurricane Center for information on Alberto. 

&&

.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
VFR conditions expected to prevail at the KALB/KPOU/KGFL/KPSF 
terminals through the 24 hour TAF period ending 18Z Saturday, 
with mainly just some passing high level cirrus clouds. SCT mid 
level clouds are expected to develop at KGFL tonight as a 
disturbance moves across far northern NY. There will be a PROB30
for thunderstorms at KGFL after 17Z. 

Winds today will be west-southwest and increasing to 10-15 kts 
with gusts around 20-25 kts becoming common during the 
afternoon as mixing potential increases. Winds speeds will 
decrease to less than 10 kts after sunset and remain between 5
and 8 kts through the end of the TAF period.

Outlook...

Saturday Night: Moderate Operational Impact. Scattered SHRA...TSRA.
Sunday: Moderate Operational Impact. Scattered SHRA.
Sunday Night: Moderate Operational Impact. Scattered SHRA.
Memorial Day: Moderate Operational Impact. Chance of SHRA...TSRA.
Monday Night:  Slight Chance of SHRA...TSRA.
Tuesday: No Operational Impact. NO SIG WX.
Tuesday Night: No Operational Impact. NO SIG WX.
Wednesday: No Operational Impact. NO SIG WX.

&&

.FIRE WEATHER...
Warm conditions, with increasing humidity, will continue 
through Saturday as high pressure builds off of the Atlantic 
coast. Some showers or thunderstorms are possible over the 
holiday weekend.

RH values recover to 70 to 90 percent. RH values drop to 30 to 
55 percent Saturday.

Gusty west to south west winds this evening will diminish to 15
mph or less tonight. West to southwest winds around 15 mph 
Saturday become southeast at 15 mph or less late Saturday 
afternoon.

&&

.HYDROLOGY...
No hydrologic issues are anticipated over the next few days.

Dry weather is expected to continue through tonight with high 
pressure in control. As a result, rivers, streams, lakes, ponds,
reservoirs, brooks, creeks and kills will remain fairly steady 
over the next few days. 

Our next chance for scattered showers and possible thunderstorms
will be over the holiday weekend. Northern and central areas 
will have the best chance of seeing a shower or thunderstorm on 
Saturday, with better chances across the remainder of the area 
for Sunday into Monday. Rainfall amounts will be highly variable
due to thunderstorm activity and some locations may stay 
completely dry.

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.

&&

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

&&

$$
SYNOPSIS...NAS
NEAR TERM...11/NAS
SHORT TERM...NAS/JPV/JVM
LONG TERM...IAA
AVIATION...11/JPV
FIRE WEATHER...NAS/JVM
HYDROLOGY...NAS/JVM