Scientific Forecaster Discussion
fxus63 kpah 180944
Area forecast discussion
National Weather Service Paducah Kentucky
344 am CST Mon Nov 18 2019
Short term...(today through Wednesday night)
issued at 340 am CST Mon Nov 18 2019
Today will be another seasonably cool and rain-free day as a weak
surface ridge drifts east across the region. Tonight, a weak
clipper type system will dive southeast through the plains and
into the forecast area. However, the system is expected to be
rather moisture starved, similar to last night's system, so not
expecting much of an overall impact.
Hoping to get back to some sunshine in the wake of the system on
Tuesday as high pressure builds in from the west. This high will
not be of Canadian origin, and temperatures may actually climb to
near or slightly above normal levels by Tuesday afternoon. Most
locations will see highs in the lower to mid 50s. Wednesday,
however, looks to be the pick day of the week as an upper level
ridge builds east into the region, and winds turn more southerly.
Expect afternoon temperatures to flirt with 60 degrees or so at
As the upper high shifts east Wednesday night, the flow aloft will
become more southwesterly, and moisture will begin to increase
ahead of low pressure lifting northeast from the Central Plains
to the Midwest states. A cold front trailing south from this low
will move east into MO by late Wednesday night. Scattered showers
will be possible ahead of this front after midnight, mainly along
and N/W of the Ohio River. Rain amounts should stay on the light
Long term...(thursday through sunday)
issued at 340 am CST Mon Nov 18 2019
At the start of the long term period, a low pressure system will
be situated in eastern Iowa with a cold front trailing
south/southwestward into MO and into OK. As this front pushes east
throughout the day, we should see an increase in rain chances.
Placement of highest pops during the day on Thursday continues to
be a challenge at this juncture due to timing differences.
However, the bigger change from yesterday is additional widespread
precipitation development noted in the latest data for Thursday
night into Friday, as low pressure develops on the slowly moving
cold front. Strong southwesterly flow aloft will continue during
this time frame with plenty of moisture to work with. In fact, dew
points will surge into the 55 to 60 degree range during the day on
Thursday. Pops should be raised significantly as all of the latest
guidance is portraying this scenario. Highest pops will be situated
across the southern half of the area, more in line with the GFS
precip ensemble mean.
Toward Friday into Friday night, there are substantial differences
on exactly when this system will exit the area. This even has an
affect on sensible weather elements going into Saturday. A lot will
depend on just how well developed the surface low becomes. The upper
flow pattern is vastly different between the deterministic models
with the GFS/GFS ensemble mean indicating a positively tiled open
wave and the Euro/Canadian showing a closed off system (hence
slower). Will try to trend toward lower pops by Friday night into
Given these timing differences, there is big bust potential on
Friday night's lows as well. Some fairly large gradients will also
be possible across the area during other time periods. However, if
we clear out, temperatures will drop but no wintry precipitation
should occur Friday night, but if the system is slower to move out,
we'll have lingering precipitation, but it should be liquid. There
are 10 to 20 degree spreads in the temperatures amongst the GFS
ensemble members as well as the Euro ensembles, so temperatures will
continue to be troublesome to forecast right now for the late week
into the weekend.
Needless to say, the forecast for the Thursday through Saturday time
frame will definitely be going through some changes over the next
few days as models obtain better consensus.
issued at 1122 PM CST sun Nov 17 2019
With the 06z Monday weather forecast office pah taf issuance, added some MVFR ceilings
through 18z for the taf locations to reflect the lower ceilings
associated with the passage of the the mid-upper level trough/low
moving through the area overnight and through Monday morning.
Visibility restrictions may periodically move into upper MVFR
category, but for the most part kept visibilities in the VFR
category for most of the forecast period.
Did not mention vicinity or categorical rain overnight in the
tafs given the short temporal impact on aviation, given the
overall isolated coverage.