Area forecast discussion
National Weather Service Albany New York
737 am EDT Sat may 25 2013
Synopsis...
a coastal storm will promote unseasonably cool and showery
weather for much of this beginning Holiday weekend. High pressure
will build across the northeast for the latter half of Memorial
Day weekend and early next week...bringing a return of warmer
weather.
&&
Near term /through tonight/...
as of 630 am EDT...bands of rain around the periphery of the nearly
vertical stacked low continues to impact most of eastern New York and
adjacent western New England. As this low becomes
captured...expectations are for this surface low to retrograde
somewhat later this afternoon. Latest MOS and lav/lamp guidance
continue to support a rather cold day with temperatures not moving
too much from current values. The lower level wind magnitudes per
the rap/ruc13 continue to support an increasing wind field today
with gusts over 30kts at times. So main update was to pop/weather grid
this morning and hourly temp/dewpt.
Previous disc...
upper low becoming negatively tilted over New England will capture
the surface low over Cape Cod later today for this system to
become vertically stacked. This will keep a persistent northerly
flow of moisture and cool air through the near term period. The
850-500 layer q-vector convergence remains quite strong through
the day to keep periods of rain in the forecast. However...per the
dual pol data...the freezing levels continues to drop and we would
not be surprised to hear/see some sleet and/or graupel this morning
across the higher terrain. The other issue today will be the winds
as h925-h850 wind magnitudes climb to and above 50kts. While we
will not completely mix to these layers...the potential does exist
for some of this higher momentum air to Transfer during the
daylight hours. Apparent temperatures /wind chills/ today will average
into the 30s for most of the area with high temperatures only into
the 40s. Our normal high for today in Albany is 72...Glens Falls
is 70...and 74 degrees in Poughkeepsie. In fact...with our current
forecast high in the 40s for Albany...this would set a new low
maximum temperature /previous record is 51 degrees in 1967/.
A vertically stacked low is forecast to be in the vicinity of the
Gulf of Maine. Deformation axis remains across most of the region
with this zone of influence weakening from southwest to northeast
overnight. This will keep probability of precipitation rather high along with a brisk
northerly flow as the pressure gradient remains tight but not as
gusty due to limited mixing potential. MOS guidance continues to
be a little cooler as we followed a blended approach for the
overnight lows into the upper 30s and lower 40s cwa-wide. The
chance for another record for Albany as low mean temperature for
the date is 44.5 set in 1925. Due to the elevated wind
magnitudes and precipitation...this would preclude any mention of
frost for the region. However...with lowering wet bulb zero
heights...the chance for some wintry type mixed precipitation
increases for the higher terrain.
&&
Short term /Sunday through Monday/...
Sunday...the vertically stacked low begins to fill further and become
further removed from the region with improving conditions from
southwest to northeast with respect to precipitation coverage. Sky
coverage may take some additional time but thoughts are we should
see some peaks of the sunshine later in the afternoon and just
before sunset. The pressure gradient remains rather tight which
should result in a brisk day once again with occasional gusts
around 30kts as per the bufr profiles we effectively mix close to
h850. Given some breaks in the overcast expected along with drier
conditions...afternoon high temperatures should climb back into
the 50s for most of the area.
Sunday night into Monday...surface high pressure and rising
heights aloft will provide tranquil conditions with mainly clear
skies. The main concern during this time frame will be frost and
freeze conditions. The combination of clearing skies Sunday night
and the surface ridge building in from the Great Lakes
region...winds should decouple for near ideal radiational cooling
conditions. Portions of the Adirondacks could experience
temperatures dipping at or below freezing with the remainder of
the higher terrain experiencing frost conditions. After
collaboration...we will highlight in the severe weather potential statement and make further
adjustments before issuing freeze watches. As late may sunshine
returns for Memorial Day...forecast highs are expected to climb
toward seasonable values /lower 70s for valley locations and 60s
for the higher terrain/.
&&
Long term /Monday night through Friday/...
the extended period will feature a warming trend with a return to
above normal warmth by late in the week.
An upper trough will continue to be moving away from the area on
Monday night as weak ridging builds into the Great Lakes. At the
surface...high pressure will be situated over the area. With clear skies
and light winds expected...another chilly night is expected with
mins from the lower 30s in the Adirondacks to the lower to middle 40s
for the Hudson Valley and northwest CT. There could be some continued
frost/freeze issues for southern greens and southern Adirondacks.
High pressure will slowly shift offshore for Tuesday...allowing for
a light S-SW wind to take over at low levels. Warm advection will
begin at middle levels...especially by late in the day. Although skies will
start off sunny...some high clouds may start to spread into the
region by afternoon. Maximum temperatures will be warmer than Monday...with middle to
upper 70s in many areas.
Ridging will begin to become stronger across the Ohio Valley...middle
Atlantic and southeast for the middle week period. A surface warm front
will be pushing across the area for Tuesday night...and a shortwave
will slide across the top of ridge across southern Canada on
Wednesday. These two features will allow for a chance for some showers
and thunderstorms...especially for northern parts of the region. Min temperatures
on Tuesday night won't be as cool...with middle 40s to middle 50s. Highs
on Wednesday will be much warmer...with 80s for most places...as 850 hpa
temperatures surge to 14 to 16 degrees c. Depending on how much instability
is in place...we will have to monitor the potential for strong
storms on Wednesday...as this is a climatological favored time for
severe weather in our area.
Temperatures will continue to be warm for the remainder of the week with
80s expected as the region remains dominated by the strong ridge at
500 hpa. With our area being on the northern fringe of the
ridge...we will have to watch if any additional shortwaves passing
across the northern periphery of the ridge allow for additional
chances for thunderstorm activity. The 00z European model (ecmwf) shows this is a
possibility for Thursday...so will keep a slight chance for thunderstorms in the
forecast. Otherwise...it looks dry and warm and increasingly humid
to end the work week.
&&
Aviation /12z Saturday through Wednesday/...
a slow moving coastal storm will allow for periods of rain
throughout the day today. A steady rain is currently affecting all
the eastern New York and western New England terminals. While the rain
will be rather light in intensity...it should continue through much
of the day. By late in the day...the rain may be more showery in
coverage for this evening and into the overnight hours.
Flying conditions are generally MVFR...mainly for ceilings. This looks
to continue through the day. Model soundings would suggest that
flying conditions will predominately stay MVFR throughout the day.
However...based off the recent trend in observations...a brief
period of IFR for visibilities is possible at kalb this morning. Kpsf may
also see low end MVFR conditions for ceilings...and it wouldn/T take
much for a brief reduction to IFR conditions at that terminal as
well.
The flow around the storm will make for gusty north-northwest winds...especially for
the afternoon and into the evening hours. A few gusts of 25-30 kts will
be possible...especially for kalb.
Outlook...
sun...VFR/MVFR...chc -shra. Breezy north winds.
Sun night-Tue...VFR. No sig weather.
Wednesday...VFR. MVFR possible with chance PM shra/tsra.
&&
Fire weather...
no fire weather concerns through the weekend as the coastal low
remains in the vicinity keeping conditions unsettled. This will
keep relative humidity levels high despite the occasionally gusty
northerly wind. Drier weather is expected to return later this
weekend and into Memorial Day with near seasonable temperatures.
&&
Hydrology...
radar continues to exhibit bright banding which is resulting in
higher radar returns but rainfall amounts remain rather light.
6-hour totals where 1/2 of an inch or less with ahps river points
showing either within bank rises or near steady flows. This is
expected to continue with little to none expected Hydro issues.
Drier weather is expected later Sunday and continue into Memorial
Day. This will result in area streams and rivers to slowly recede.
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...bgm
near term...bgm
short term...bgm
long term...frugis
aviation...frugis
fire weather...bgm
hydrology...bgm
