Scientific Forecaster Discussion
fxus63 kind 201742
Area forecast discussion
National Weather Service Indianapolis in
1242 PM EST Wed Nov 20 2019
the aviation section has been updated below.
issued at 305 am EST Wed Nov 20 2019
A series of low pressure systems will bring precipitation chances
late tonight through Saturday and then again Tuesday. Thursday will
see above normal temperatures. Otherwise, look for below normal
temperatures into next week.
Near term /rest of today/...
issued at 948 am EST Wed Nov 20 2019
Low stratus and patchy fog continue to impact most of the forecast
area as of mid morning. Clearing had worked into the lower Wabash
valley but further erosion of the stratus deck was limited at best
to this point. 14z temperatures were generally in the upper 30s
and lower 40s.
The overall forecast is in good shape with just some minor
adjustments in order. High pressure will drift across the region
today and with generally weak flow aloft associated with the
high...think clouds will be stubborn in mixing out. Have continued
with a pessimistic approach to the cloud cover today...trending
towards mostly cloudy east with some sun developing west. Should
see ceilings lift over the next couple hours with patchy fog
diminishing. High temperatures ranging from the mid 40s north to
lower 50s south/southwest.
Zone and grid updates out.
Short term...(tonight through Friday night)
issued at 305 am EST Wed Nov 20 2019
Models are close enough that the National blend of models
initialization was accepted for most items.
Clouds will increase again tonight with the approach of a low
pressure system. By late tonight enough forcing will arrive for some
low pops most areas.
On Thursday a 50kt 850mb jet along with a surface warm front will
bring enough forcing and moisture to go likely or higher category
pops to most areas by mid to late morning. Pops will diminish most
areas in the afternoon as the jet exits the area, and the better
forcing moves north of the area closer to the upper system.
Thursday evening a cold front will move through, and this could
bring another area of rain. Will have high chance or low likely pops
The front will then settle south of the area Friday and Friday
night. Waves will ride along the front, and an upper low will
approach the area as well. This will keep the threat of
precipitation around for most areas, especially south.
Confidence is not great though as there remains uncertainty on how
exactly things will come together and the location where the front
will stall out.
Enough colder air may sneak into the area Friday night for some snow
to mix in with any rain, but there shouldn't be any accumulation.
Long term /Saturday through Wednesday/...
Issued at 342 am EST Wed Nov 20 2019
Chances for precipitation, possibly a rain/snow mix, continue into
Saturday as an upper wave moves across the region. Models then
indicate that a surface high pressure system, centered across the
south, will influence the Ohio Valley Sunday and Monday. This will
lead to a couple days of dry conditions and winds out of
southwest. A potent and deep trough will make its way down across
the central US then towards the Great Lakes region. This system is
expected to bring in rain and gusty winds for Tuesday and
Wednesday. Models agree in the presence and general timing of
this strong system, but lack agreement in finer details for now.
Accepted guidance for the majority of the long term forecast, but
increased the sustained winds for Tuesday and Wednesday to match
the expected conditions which could see values near 20 kts and
gusting above 30 kts.
Aviation /discussion for 201800z taf issuance/...
issued at 1242 PM EST Wed Nov 20 2019
Ceiling restrictions will linger for a few more hours...then VFR
into Thursday morning.
Low stratus remains stubborn in its erosion with trapped low level
moisture and weak flow aloft. Should see increasing sunshine at
khuf and klaf over the next hour or two but will likely take until
late afternoon at kbmg and kind before better mixing of the deck
occurs. Mainly clear skies will expand in this evening before more
substantial mid level clouds advect back into the region overnight
ahead of the next storm system lifting out of the Central Plains.
Rain will develop Thursday morning as deeper moisture expands into
the region from the west. A strong low level jet will lift into
the region and introduce the potential for low level wind shear
from mid morning into the afternoon. Ceilings will also drop back
to MVFR by midday Thursday. Light and variable flow into the
evening will transition to S/SW on Thursday.