Scientific Forecaster Discussion
fxus63 kpah 270506
Area forecast discussion
National Weather Service Paducah Kentucky
1206 am CDT Tue Jun 27 2017
issued at 1206 am CDT Tue Jun 27 2017
Updated gridded, tabular, and text forecast to reflect
elevated thunderstorm activity occurring with convection over
southeast Missouri at this time.
Update issued at 1142 PM CDT Mon Jun 26 2017
The aviation section has been updated for the 06z taf issuance.
Short term...(tonight through Wednesday night)
issued at 248 PM CDT Mon Jun 26 2017
A weak disturbance, rotating around the upper low over the Great
Lakes region, will affect our area this evening and into the
overnight hours. This will be the main concern during the short
Upper level energy is nosing in from the northwest with ongoing
showers and even a few lightning strikes noted on radar back in
central Missouri. Even have some new development nudging into
Carter County as of 2:30 PM. This activity will spread
east/southeast with the best coverage and intensity of rain
expected across southeast Missouri into far west Kentucky.
Model guidance does vary some on the timing, intensity, and
duration with the precip with this system. 12z GFS is the most
robust showing a swath of quantitative precipitation forecast up around 1" near the Hickman, Kentucky
area. 12z European model (ecmwf) is the polar opposite with less than 0.1" across
the entire area. Expecting a middle ground approach to pan out,
with amounts of 0.25" to 0.5" in our southwest counties, with
some isolated higher amounts, and then lighter amounts across the
northeast half. The 4km NAM nest seems to have a good handle on
the current activity and shows the best coverage and highest
amounts from southeast Missouri into northwest Tennessee. Tending
to agree with this solution and wouldn't be surprised to see most
of the activity south of our forecast area by around 06z. Even if
the slower solutions pan out, the whole region will be dry by 12z.
Expecting mainly showery activity but included an isolated
mention of thunder through the evening hours to account for some
elevated instability present. The best lightning potential will be
over southeast Missouri, particularly late this afternoon and
Surface high pressure, centered just to our north tomorrow, will
gradually slide eastward to the mid-Atlantic states on Wednesday.
This will result in dry conditions during this time period. Easterly
flow tomorrow will become southerly on Wednesday ushering in
warmer and more humid conditions. Highs tomorrow in the upper 70s
to around 80 will warm into the mid to upper 80s on Wednesday.
Dewpoints will climb from the 50s tomorrow into the mid 60s in
many areas by Wednesday afternoon.
Long term...(thursday through monday)
issued at 248 PM CDT Mon Jun 26 2017
Starting Thursday, the surface high will have drifted off the East
Coast, allowing Gulf moisture to begin surging north into the
region. Forecast soundings indicate the column becomes more and more
saturated as we head into the weekend. Thursday is not looking as
good for storms as previous model runs restricting pops to along and
north of interstate64 corridor. Even Friday when scattered pops
spread across the region, moisture is still not through the
column, although adequate in the lower levels for some activity.
By this weekend it becomes more saturated through the entire
Also as we head into the weekend, a weak surface front will be
drifting into forecast area. At the same time, the nearly zonal flow
aloft will likely allow the front to stall out over some portion of
the region close to the Ohio River. In addition, on Saturday the Li's
will approach negative double digits with cape's around 2-3k during
the daylight hours. The instability decreases dramatically overnight
but we still have elevated instability. So storms will be possible
both day and night. In addition, pw's will approach 2" this weekend,
so any storms will be very efficient rain producers. Winds are
fairly unidirectional and not that strong but the instability will
be capable of producing an isolated severe storm or two. Still
believe the main concerns lie with heavy rain and lightning, with
may areas picking up a good 1-3 inches by early next week. We may
see a break in the action for awhile Sunday between ripples of
mid level energy embedded in the westerlies, but timing of these
short waves is difficult at best this far out in time.
issued at 1142 PM CDT Mon Jun 26 2017
An upper-level disturbance will continue to spread showers and an
isolated thunderstorms and rain or two southeast through southeast Missouri into the
early morning hours. This activity is expected to stay west of
kcgi and kpah, but did keep a vcsh at kcgi for a couple of hours
just in case it survives farther east than expected. Otherwise,
the forecasts are VFR and dry with light winds.