Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Blacksburg Virginia
350 am EDT sun Oct 26 2014

a cold front will move in from the northwest this morning bringing gusty
winds. High pressure will then pass across our area tonight into
Monday. The next cold front will arrive by Wednesday.


Near term /through tonight/...
as of 255 am EDT Sunday...

Frontal boundary stretching from NE PA/southeast New York southwest across the
Ohio Valley will slide southeast through the region this morning.
Airmass will dry out not really seeing much in the way of
showers early this morning...though enough convergence in the NC
mountains for isolated threat until 7 am.

Skies will be clearing in the mountains with sunny skies expected
through the day. Strong northwest flow will allow for mixing of the expect west-northwest winds of 10 to 15 miles per hour with gusts to 20-30 miles per hour.

Not seeing any cold air advection so highs today should be mild with
readings in the lower to middle 60s lower to middle 70s

Tonight...high pressure slides across the area. Skies remain clear
with winds subsiding. Lows will range from the middle 30s mountain middle to upper 40s southeast.


Short term /Monday through Wednesday night/...
as of 330 am EDT Sunday...

High pressure will be centered over our area to start the day on
Monday...making for relatively clear skies and light winds. The high
will shift rapidly southeast...passing off the Carolina coast during
the afternoon to bring southwesterly windflow to the appalachian
chain. Upper level ridging building in from the west will keep the
warm spell in tact...with afternoon highs reaching into the 70s most
locations...upper 60s at higher elevation. Monday night lows will
hold in the 50s for the most part.

Even warmer temperatures can be expected for Tuesday as Gulf air
pools ahead of an approaching cold front. Will start the day off
with abundant sunshine...with clouds increasing during the afternoon
and evening. Expect middle/upper 70s across the mountains...and low 80s
across the Piedmont for afternoon highs. Spotty showers will enter
the mountains by around midnight Wednesday as the cold front nears
the appalachian chain...with showers becoming increasingly
widespread as the night wears on.

By sunrise Wednesday...the front will be making steady progress
eastward across the mountains. Atmospheric moisture falls off
quickly with frontal passage...and with only modest atmospheric
instability...believe most locations can expect a window of only a
couple hours of shower activity...with one or two tenths of an inch
rainfall accumulation. Dry high pressure will build in quickly
behind the front...bringing clearing conditions for Wednesday
evening...with temperatures returning to more seasonal values.


Long term /Thursday through Saturday/...
as of 130 PM EDT Saturday...

More waves of energy will rotate around a upper cold pool across the
lakes Thursday into Friday. This will lead to the development of a
very deep 500 mb trough per a forecast closed upper system heading into
New England by Saturday with the main piece of shortwave energy.
Still some earlier model differences with the ec wanting to close
this off over the region while consensus favors a more progressive/
northward scenario. This should keep most of the County Warning Area between systems
Thursday through Friday with weak low pressure/associated moisture to
the southeast and shallow cold pool precipitation to the northwest. However deepening northwest
flow and passage of the final trough axis...likely to swing upslope
rain/snow showers into gear Saturday...when well below 0c 850 mb air
will advect in on strong northwest flow perhaps making for the coolest day
seen so far this fall.

This along with strong surface high pressure building in from the
west will cause a daily tapering of temperatures with highs mostly 50s to
around 60 by Friday...and perhaps only 40s west to 50s east
Saturday. Expect lows to dip below freezing mountains Friday night
and possibly across the region overnight Saturday.


Aviation /08z Sunday through Thursday/...
as of 125 am EDT Sunday...

Low level inversion in place at most sites with the stronger flow
aloft allowing for some low level wind shear concerns early this taf
period but will go away around 09z. Dealing with some MVFR to high
end IFR in southeast WV this morning mainly at blf...with VFR elsewhere.

The stratocu will clear out by dawn and mixing will commence at
all taf sites in the 14-16z time frame. West-northwest winds of 10 to 15
knots with gusts 20-30kts expected until late afternoon. Should be
VFR through the day into Sunday evening. Winds will begin to
subside after 22z.

Confidence high in all taf parameters.

Extended aviation discussion...

VFR conditions expected through Tuesday. Lower restrictions
possible Tuesday night into Wednesday with the passing of the
next front and an upper trough settling into the northeastern U.S.
VFR to return to all sites Thursday.


Fire weather...
as of 330 am EDT Sunday...

West-northwest winds will gust up to 25 miles per hour this morning into early afternoon
while the humidity tumbles into the 20s this afternoon.
Significant drying has taken place over the past week where 10
hour fuels have dropped to 7-8 percent. Due to this
enhanced Fire Danger Statement for the portions of the area will
remain in effect today.


Rnk watches/warnings/advisories...


near term...wp
long term...jh/nf
fire weather...rcs/wp

National Weather Service Glossary of Abbreviations