Area forecast discussion
National Weather Service Buffalo New York
131 am EDT Thursday Jun 20 2013
Synopsis...
high pressure anchored across New York state will slowly drift to
the East Coast today and Friday...and will continue to bring
pleasant weather to our area through Friday. As the high slides
offshore this weekend...a southwesterly return flow of warmer and
more humid air will spread across our region...eventually leading
to the chance of a few showers and thunderstorms by Saturday night
or Sunday.
&&
Near term /through today/...
temperatures will continue to drop overnight under ideal radiational
cooling conditions. Aside from a narrow band of high clouds which
will quickly cross portions of the area overnight...skies will be
clear...allowing temperatures to drop back into the 40s overnight...
with a few spots in the valleys of the southern tier and north
country dipping to around the 40 degree mark.
Like last night some River Valley fog may form through the southern
tier and into the valleys of Wyoming and southern Livingston County.
With the dewpoint depression about the same as last night...will
include valley fog in the same places it developed last night.
This area of high pressure will begin to slip to the eastern
Seaboard Thursday. Aloft building 500 hpa heights...and 850 hpa
temperatures warming to about +10 to +12c will promote a warmer day
Thursday. Highs will climb into the 70s across much of the
region...which is much closer to normal. Though the humidity will
rise some also...dew points will remain around 50f or lower...which
is still comfortable.
Again will see some afternoon clouds forming through the southern
tier with the daytime instability. Expect the greatest number of
fair weather cumulus over the hills of the interior southern tier
where 850-500 hpa layer moisture is deepest.
&&
Short term /tonight through Saturday night/...
multi model and ensemble consensus continues to build middle and upper
level ridge axis across the lower lakes region for much of the
period...before shifting it eastward in association with the ejection
of a significant northern rockies shortwave trough into northern
Great Lakes by Saturday. Certainly looks like a precipitation free
period in the Thursday night through at least Friday night time
frame with warm middle level temperatures underneath upper ridge. Weak
low level flow should limit the northern extend of the Theta-E
advection and result in effective middle level capping inversion
through this period.
Saturday...we continued the low end probability for convection
during the afternoon as the upstream sharp middle level trough makes
its eastward progression and some inherent breakdown of the middle
level ridge takes place. Better return flow brings more low level
moisture northward with lake breeze convergence areas the most
likely trigger for any afternoon convection.
Gradually warming through the period with highs in the upper 70s to
lower 80s on Friday and into the lower to middle 80s by Saturday.
&&
Long term /Sunday through Wednesday/...
some degree of differences arise in the model guidance between the
GFS/European model (ecmwf) regarding the potential for showers and thunderstorms
development during this period.
Now for the details...latest 12z GFS guidance package suggests that the
lower Great Lakes will be on the northwestern edge of an expansive
ridge of high pressure building into southern Continental U.S.. return flow
around this ridge of high pressure will pump an ever increasing warm
and moist airmass into the region. This will keep the potential for
a chance of daily showers and thunderstorms in the forecast.
The European model (ecmwf) shows a broad but Flat Ridge of high pressure over the
southern Continental U.S. With zonal flow over the Great Lakes region. Several
weak shortwaves embedded within this flow will bring a chance for
showers/thunderstorms across the region with brief lull between
shortwaves. However...one thing is for sure both models show that the
first full week of Summer will exhibit to some degree warmer than
normal temperatures. Medium range MOS guidance and wpc show maximum temperatures
ranging between 82f-87f across most of interior sections of western
and north central New York during this period.
&&
Aviation /06z Thursday through Monday/...
sprawling high pressure centered over New York state will slowly
drift to the Atlantic coastline through tonight. Aside from some
patchy fog and associated restrictions in the southern tier valleys
early this morning...conditions will remain VFR through the taf
period.
Outlook...
Friday...VFR.
Saturday through Monday...VFR with a chance of showers and
thunderstorms.
&&
Marine...
broad high pressure anchored across New York state will slowly
settle to the East Coast today and Friday. This feature will bring
continued fair weather through Friday...along with light winds and
negligible waves.
&&
Buf watches/warnings/advisories...
New York...none.
Marine...none.
&&
$$
Synopsis...jjr
near term...apffel/jjr/Thomas
short term...tma
long term...Arkansas
aviation...jjr
marine...jjr
