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Area forecast discussion 
National Weather Service Paducah Kentucky
500 PM CST Thursday Nov 26 2015

issued at 457 PM CST Thursday Nov 26 2015

Updated aviation discussion for 00z taf issuance.


Short term...(this evening through Saturday night)
issued at 208 PM CST Thursday Nov 26 2015

No changes planned to the Flash Flood Watch with this forecast

The 12z models continued to trend slower with the onset, and also
with the cold frontal passage through our region. It may linger
over west Kentucky into Saturday evening. With the slow-moving
cold front aligned parallel to the flow aloft and precipitable
water values around 1.5", which is above the 99th percentile for
November and December, a prolonged period of moderate to heavy
rainfall is highly likely. The only thing missing for a major
flash flood event is instability and the associated high
convective rain rates.

It will take some time for the runoff to pile up, but by Friday
night much of the watch area will be ripe for flooding with
continued moderate to heavy rain forecast into Saturday. The
current forecast now has 3-4" rainfall totals over much of the
watch area, with the greatest amounts over the westernmost
portions of southeast Missouri. We continue to feel that the
flooding threat will be greatest out there.

If there were to be any tweaks to the Flash Flood Watch, it would
be too lop off the northern three counties and end it at 00z
Sunday, as storm totals are well under 3" up there, and the
consensus of the 12z guidance brings the heavier rain to an end
Saturday afternoon. Will let the midshift re-evaluate with the
00z guidance and make the change if the model trends are

In the near term, have spread isolated to scattered showers
northward to areas west of I-57 in southern Illinois through
sunset, as weak radar echoes have been rather persistent so far
this afternoon. This evening should be dry, and most of the area
will remain dry overnight as well before the more solid
precipitation overspreads the region into Friday morning.

As for temperatures, readings have climbed into the lower 70s
over the pennyrile where skies are mostly sunny this afternoon.
With all of the moisture around and dewpoints possibly climbing up
to the 60 degree mark ahead of the front, generally stayed on the
warm side of guidance through Saturday, and then trended closer to
consensus for lows Saturday night.

Long term...(sunday through thursday)
issued at 208 PM CST Thursday Nov 26 2015

At this time, the expected contribution for any lingering rain from
Sunday through Monday night will range from 6/10ths of an inch near
Mount Vernon Illinois to 1.40 inches near Fort Campbell Kentucky.

Overnight numerical model runs attempted to overspread precipitation
a little further north, but the on-going trend has been to keep the
highest quantitative precipitation forecast further south along and south of the Ohio River and much
closer to the Tennessee Kentucky border, back to the Missouri
bootheel. The 12z Thursday model guidance (namely the GFS and
canadian) move that direction versus the NAM-WRF suite and the
European model (ecmwf). The European model (ecmwf) has been all over the place with the mid-level
forcing (which is key to enhancing precipitation along and behind
the cold frontal zone. The GFS and Canadian have been more
consistent in displacing the forcing over southeast MO/southern
Illinois/southwest in vs. The European model (ecmwf) and NAM. This displacement would allow
for a broader swath of precipitation across the area, but would
limit the areal coverage of high precipitation within the weather forecast office pah
forecast area in the extended period.

No plans for any hydrologic statement to cover the additional
precipitation for Sunday and Monday. Most persistent in time and
space will be along travel routes in west Kentucky going into
Monday. Six hourly amounts are expected to remain less than a third
of an inch Sunday into Monday and should drain sufficiently to avoid
any significant flooding concerns.

Only minor tweeks in temperature, dewpoint, winds, and cloud cover.

Should see dry weather return from the west late Monday night and
spread east on Tuesday. This is in line with model run projections
from late last week.


issued at 457 PM CST Thursday Nov 26 2015

Flight conditions are poised to deteriorate over the next 24 hours
as a weather system taking shape makes its approach. MVFR decks
are on the horizon and will be incoming overnight...with rain
chances spiking by tmrw...when MVFR cigs/vsbys will have become
predominant at all sites. And as the day wears on, IFR cigs/vsbys
will be introduced as rain sets in and pockets of heavier rains
occur...esp later in the day. South winds will pick up and
becoming gusty as well.


Pah watches/warnings/advisories...
Illinois...Flash Flood Watch from Friday evening through Saturday evening
for ilz080-084-088-092-093.

MO...Flash Flood Watch from Friday evening through Saturday evening
for moz076-086-087-100-107>112-114.



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