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fxus63 kpah 161128 

Area forecast discussion
National Weather Service Paducah Kentucky
628 am CDT Mon Sep 16 2019

issued at 617 am CDT Monday Sep 16 2019

Update for 12z tafs


Short term...(today through Wednesday night)
issued at 203 am CDT Monday Sep 16 2019

Hot weather continues as an upper level ridge positions itself
over the region.

Making an adjustment to going forecast. Adding a small chance of
thunderstorms this afternoon into the early evening hours. A weak
boundary will be pushing south across the area. Exact
location/timing depends upon the model. Thinking right now is that
it will be along the Ohio River near evv at 20z.

South and along the boundary, in the higher precipitable water air, cape values
will be 1500-3000 j/kg and there will be some weak speed
convergence at 925mb to help aid in any development. Several of
the cams have spotty thunderstorms across the area. Coverage
should be minimal, but do feel that there will be a couple storms.
No rain over the past 20 days has resulted in very dry
conditions. At least a few locations may see some badly needed
rainfall. May be some gusty winds with dry adiabatic lapse rates
forecast from 800mb down to the surface according to BUFKIT

Dew points will still be rather high today so heat index values up
to 102 are possible at various locations across the area. Slightly
lower dew points will filter into the area Tuesday and Wednesday
which will decrease the coverage of 100 plus heat index values.
But they will not completely disappear due to well above
temperatures, especially over semo, far west Kentucky, and
southwest Illinois.

Long term...(thursday through sunday)
issued at 203 am CDT Monday Sep 16 2019

The mean ridge resulting in our prolonged warm/dry spell is still
intact at the beginning of the long term period, with life still to
live as 500 mb heights near 590 dm hold across nearly the entirety of
the Ohio and Mississippi River valleys/at least our portion thereof.
The surface ridge has shifted east, resulting in the return of low
level southerlies that nudge dew points upward a few degrees toward
the end of the work week. Strong height falls in the High Plains
will drive a storm system our direction, and it's the beginning of
this combined with the aforementioned that the models have
consistently pinged upon for a slight chance mention of pcpn in our
semo Ozarks Friday PM. We cannot argue this possibility out, so will
leave the mean/blend untouched with this mention.

Pattern evolution will result in a relative break in the hot/dry
spell over the weekend, as the High Plains storm system bears down
on the Great Lakes, and drives a cold front to the doorstep of our
forecast area. With Humberto out to sea, but not too distant off the coast, the
mean ridge that has been so dominant becomes quashed to the
southeast U.S. Increasing moisture in the column overall should be
amply supportive for introductory pops as the front slides into the
picture Saturday night, and as the parent storm energy moves the
base of the mean long wave trof across the Great Lakes, thru the day
on Sunday as well. These pops/increase in clouds will yield a
relative cool off of 5 to 10f by Sunday, from the week long plus
preceding days run of upper 80s-lower 90s.


Aviation...(for the 12z tafs through 12z Tuesday morning)
issued at 617 am CDT Monday Sep 16 2019

Patchy fog seems to be moving across the sensors at kcgi/kmvn.
Otherwise VFR. Isolated storms are expected this afternoon but for
now keeping them out of the tafs. Early this evening, storms will
dissipate. After about 10z tomorrow, fog should be a little more
widespread which will occasionally contribute to MVFR/IFR


Pah watches/warnings/advisories...


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