Scientific Forecaster Discussion
Area forecast discussion
National Weather Service State College PA
931 am EDT Monday may 25 2015
a large area of high pressure will be anchored off the Delaware-Maryland-Virginia
coast through early in the upcoming week. After a mainly dry and
very warm day today...this setup will lead to increasing warmth
and humidity with a daily...mainly afternoon and early evening
chance of showers and thunderstorms.
Near term /until 6 PM this evening/...
warm front well to the north of our area this morning...extending
from the Niagara Frontier of western New York...to the eastern
Finger Lakes region.
An area of generally sunny skies occupies the warm sector over the
central Appalachians and middle Atlantic Piedmont...beneath a sharp
upper ridge axis.
Precipitable waters of just over 1 inch this morning...will increase to
around 1.5 inches this afternoon across much of central and
Slightly warming temperatures aloft /between 700 and 600 mb/ will likely
put a lid on the very thin cape of just a few hundred j/kg this
afternoon and early this evening. So...aside from an isolate late
day shower across the northwest mountains of Penn...expect a dry and very warm
Memorial Day to Honor and celebrate those who sacrificed for our
Maximum temperatures this afternoon will vary from around 80f across the northern
and western mountains...to the middle 80s throughout the lower susq valley.
Short term /6 PM this evening through 6 PM Tuesday/...
precipitable waters continue to rise through the short term and will get above
1.75 inches by Tuesday afternoon. The deep southwesterly flow will
bring remnant mesoscale convective vortex/S in from the very active plains convection.
These weak and difficult to capture features will doubtlessly
touch off rain showers/thunderstorms and rain as they cross the area. Without much skill at
timing these things...the best forecast is one of a higher chance in
the afternoon. Storm Prediction Center does bring a marginal risk up and over much of
the County Warning Area for day 2 - Tuesday/Tuesday night. Will just mention in the severe weather potential statement
since it may just be too cloudy to allow for deep convection. Maximum
temperatures may actually be a degree or two cooler on Tuesday with more clouds
than will be around during the day Monday/today. Neverless...probability of precipitation
will be painted higher Tuesday with a widespread 40-50 percent over
most of the area. Will keep them lower in the southeast - where they will
be farther from the forcing and under more suppressive influence
from the upper ridge.
Long term /Tuesday night through Sunday/...
the ridge will tilt eastward and the flow will shift to the
southeast as an upper level low begins to dig into the Upper Middle
west...and extend down through the Ohio Valley. The 500 mb
anomalous ridge will still exert its affect on the region as
temperatures should remain warmer than normal through the period.
Dewpoints will be mainly in the 50s the first part of next week
for most of the area. Southeast PA will likely see dewpoints in the 60 to
65 degree range...but not really that high for late may. Warm
front also forecast to lift well north of the area on Tuesday.
Overall...temperatures should stay above normal as the anomalous
ridge keeps the cooler air up north...and precipitation chances
increase through the middle and later half of the week in frontal
passage. Another...stronger cold front with decent upper level
moisture should move through the region next weekend.
Aviation /13z Monday through Friday/...
the flight category will predominantly remain VFR through much of
the upcoming week. Any restrictions will likely be limited to
predawn/early morning fog or scattered afternoon thunderstorms.
Tue-Fri...patchy a.M. MVFR fog/br. Isolated-scattered p.M. Thunderstorms.