813 
fxus61 kaly 172336 
afdaly 


Area forecast discussion 
National Weather Service Albany New York 
736 PM EDT Wednesday Mar 17 2010 


Synopsis... 
high pressure will bring clear to partly cloudy skies and 
unseasonably warm days to the region through Saturday...after 
which much cooler and unsettled weather will return starting 
Monday. 


&& 


Near term /until 6 am Thursday morning/... 
after a picture perfect day today...with the high at Albany 
in the low 60s...temperatures will rapidly cool off after the 
sun GOES down as conditions will be nearly ideal for radiational 
cooling...clear skies...light southwesterly winds...and even 
some snow cover across the Adirondacks and the higher terrain 
of the Catskills...helderbergs...Berkshires...and southern 
Vermont. The air across the region was very dry today with 
dew points mostly in the teens and twenties. The 12z aly 
sounding had a warm nose around 960 hpa of 45 degrees just 
above a surface inversion. For overnight lows we are looking 
for the middle 30s in the capital region and the middle and upper 
20s across the surrounding higher terrain...especially in 
valleys surrounded by snow covered hillsides. 


&& 


Short term /6 am Thursday morning through Friday night/... 
the same airmass will remain over the region through Friday with 
clear to partly cloudy skies on Thursday. A back door cold front 
will approach northern New York...but will stall north of the forecast 
area late Thursday night as a surface low moves across eastern 
Canada on the back side of a weak ridge at 500 hpa. Low level 
winds will back around to a west-southwest direction with the front retreating 
north Ward Friday afternoon and night. Time height profiles suggest 
there will be considerable high clouds...and perhaps some low and 
midlevel clouds as well...on Friday...especially in the afternoon 
but some sunshine should get through and we are not looking at a 
dreary gray day. Highs both days will range from the upper 40s to 
the middle 60s...with some of the warmer areas like the capital 
district nearly 20 degrees above normal. 


Lows Thursday night will be about five degrees warmer than 
tonight...ranging from the upper 20s across the Adirondacks to 
around 40 in the capital district. It will be a few degrees 
warmer Friday night...with more cloudiness...with lows from 
the upper 30s north to the middle 40s in the capital region. 


Winds will be westerly and pick up to between 15 and 20 miles per hour... 
especially across the higher terrain...Thursday...become nearly 
calm Thursday night...then pick up again Friday to about the 
same speeds. 


&& 


Long term /Saturday through Wednesday/... 
high pressure just off the eastern Seaboard will allow for a warm SW 
flow of air across the region on Saturday. This will allow for highs 
to reach well into the 60s across all valley areas...which will be 
nearly 20 degrees above normal. 


Clouds will begin to spread into the region by Saturday night ahead 
of an approaching frontal system. This will allow for low temperatures to 
be a bit milder than recent days...with 40s from the capital region 
southward. 


Mainly cloudy skies are expected for Sunday. The latest 12 UTC GFS 
and European model (ecmwf) disagree on the exact timing of the approaching frontal 
system...with the GFS being faster...bringing most of the precipitation for 
Sat evening/Sat night...while the European model (ecmwf) has the precipitation arriving late 
Sunday night into Monday morning. For now...have gone with a blend 
of these solutions...with the best chance of precipitation of rain during 
Sunday night. This frontal boundary will have a tight thermal 
gradient associated with it...as temperatures will quickly cool down behind 
the front. For now...will not include thunder in the grids as the 12 
UTC GFS keeps showalter values greater than zero for Sat night. 
Also...surface winds may become gusty just ahead...along...and behind 
this frontal boundary...as the 850 hpa low level jet increases to 
about 40 kts according to both the 12 UTC GFS/European model (ecmwf) around the time 
of the frontal passage. 


In the wake of the front for Monday...maximum temperatures will only reach the 
30s to middle 40s across the region. With 850 hpa temperatures crashing to 
as low as -13 degrees c across the dacks...wet snow will mix with 
the rain showers at times...mainly across the higher terrain...as 
scattered lingering showers continue behind the front due to the upper 
level trough moving across the area. 


Precipitation should generally shut off by Monday night into Tuesday...as 
high pressure moves into the region. This will allow for temperatures to 
slowly rebound back towards normal levels by middle week. 


&& 


Aviation /00z Thursday through Monday/... 
VFR conditions will continue at kgfl...kalb and kpou through 00z 
Friday. High pressure will remain in control of our weather with 
only a few passing high level cirrus clouds moving through the 
area. 


Winds will be light and variable overnight at 5 kts or less. Winds 
will then become northwest at 7-11 kts after 15z Thursday. 


Outlook... 
Thu-Sat...VFR...no sig weather. 
Sun...VFR/MVFR...chc rain showers late. 
Monday...MVFR...chc rain showers. 


&& 


Fire weather... 
fire weather starts this afternoon... 


Gusty winds up to 20-25 miles per hour and relative humidity values down 
30-35 percent Thursday afternoon... 


Due to the lack of rainfall in the Hudson Valley from the past 
storm...fire weather will start today. We apologize for the short 
notice. 


Relative humidity values once again have tumbled to below 30 percent during the 
afternoon with winds gusting generally just under 25 miles per hour. 


The wind will diminish after Sundown...down to around 5 miles per hour in the 
valleys...closer to 10 miles per hour across the hilltops from a westerly 
direction. Only a partial recovery expected as relative humidity values reach in 
the 75-90 percent...except closer to 100 percent over the higher 
mountain tops. 


By Thursday afternoon...with more sunshine...the wind will increase 
to 10-15 miles per hour...with some gusts closer to 25 miles per hour. 


There is a low chance we could reach red flag conditions in the 
Hudson Valley tomorrow afternoon...but right now the threat is less 
than 50 so no fire watch (yellow flag) will be issued. A back door 
cold front might actually increase moisture a little bit. 


We expect closer to a full recovery Thursday night as relative humidity values 
reach 90-100 percent with winds going light and variable. With a few 
more clouds...the wind is expected to remain light and variable 
Friday (under 10 mph). Relative humidity values will once again drop into the 
30s. 


The next threat of a wetting rain is not until Sunday night. 


&& 


Hydrology... 
the Housatonic River remains above flood stage at Falls Village 
in western Connecticut. Elsewhere it has dropped below flood. 


Flooding also persists along Springtown Road in the town of New 
Paltz in Ulster County. This is a flood prone area along the 
Wallkill River. The Wallkill has been nearly stationary around 
8.5 feet at Gardiner a few miles upstream. 


Dry conditions are expected through the next 4 days. With warm days 
and cool nights...diurnal trends in runoff due to snow melt will 
occur in the mountains. Water equivalent values in the snowpack of 
5-12 inches are currently present in portions of the Adirondacks... 
Catskills...southern Green Mountains and Berkshires. 


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. 
New York...none. 
Massachusetts...none. 
Vermont...none. 


&& 


$$ 
Synopsis...rck 
near term...rck 
short term...rck 
long term...frugis 
aviation...11 
fire weather...hwjiv 
hydrology...rck 

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