Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Pittsburgh PA
202 am EDT Friday Sep 4 2015
warm and humid conditions will continue through the weekend.
Near term /through today/...
overnight will be focused on weakening complex...associated with a
rather vigorous shortwave...that will drift south-southeastward
through Ohio. Latest model data indicates a weakening of the upper
level support as it encounters subsidence moving northeast on back
side of trough and the wave itself shears northward back toward
the main upper low. Hires model data supports the idea that
activity will diminish as it moves southward. Latest radar imagery
shows this decrease in intensity as well and Sat pics...in
correlation...are showing warming cloud tops. Have increased probability of precipitation
across Ohio overnight and included the mention of
thunder...although it will be isolated.
Slight to low chance diurnally supported convection is again
expected later today with weak shortwave support. No change to
the warm and humid.
Short term /tonight through Sunday/...
warmth and humidity will continue to plague the region this
weekend as broad surface high is projected to build westward
across PA under a strengthening upper ridge. Increased subsidence
and warmth aloft should inhibit diurnal convection.
Long term /Sunday night through Thursday/...
the strong middle/upper ridge is prognosticated to remain through early next
week...with continued warm and muggy conditions. Relief from the
quite warm conditions may come with cold front later Wednesday
into Thursday...as well as an increasing chance for thunderstorms.
Aviation /06z Friday through Tuesday/...
MVFR conditions will be fairly common overnight...except in the
immediate wake of the outflow boundary emanating southeastward
across eastern Ohio from around kzzv to just north of khlg.
Conditions will briefly be VFR there due to enhanced surface
mixing. However...rainfall yesterday has allowed for ample
boundary layer moisture to reside across all sites for MVFR
conditions to redevelop or continue...with local LIFR conditions
where the most rain fall today...such as in the valley around
khlg. Conditions will improve by noon today...however a few ts
will be possible by afternoon...though coverage and timing is too
uncertain for anything more than prob30 wording at the moment.
Outlook...Friday through Tuesday...
brief restrictions are anticipated in early morning fog.