Area Forecast Discussion
Issued by NWS Paducah, KY
FXUS63 KPAH 020824
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PADUCAH KY
324 AM CDT Sat Aug 2 2014
.SHORT TERM...(Today through Monday)
Issued at 324 AM CDT SAT AUG 2 2014
The primary mid/upper-level trough was located over central
Illinois as of 07Z. This has apparently provided enough lift to
sustain a very small cluster of convection through the evening and
into the early morning hours right along our northern border areas
of southern Illinois. Scattered showers and a few storms have most
recently developed southward into the northern Pennyrile region.
All of this activity is slowly progressing eastward and should
push east of the area by sunrise, as the upper trough pushes east
of the area.
With the primary trough now expected to be east of the area
today, there is little support for even slight chance PoPs this
afternoon. The NAM soundings had been indicating deep instability,
but tonight`s 00Z run is a bit lacking. Bottom line is that all
PoPs were pulled from today`s forecast.
Weak surface high pressure will build southward into the area
tonight and Sunday, as another weak mid/upper-level trough pushes
southeast into the region. Any convection associated with this
feature Sunday is confined to Iowa and northern Illinois, in an
area of low-level warm advection. The upper trough outruns that
low-level support as it descends on our region and the dry surface
high in place here, so will keep Sunday and Sunday night dry.
The 00Z NAM and GFS also try to push convection southeast toward
our region on Monday, but the dry surface high apparently wins out
again. Will keep Monday dry, but will have to keep an eye on
southern Illinois and southeast Missouri for possible addition of
PoPs in later shifts, if the surface high is not as dominant as it
appears it will be now.
As for temperatures, readings this afternoon should be similar to
yesterday`s levels in most locations. Northeast flow in the low-
levels will bring in drier air, which may allow for a degree or
two more warming for Sunday. As heights rise on Monday,
temperatures will climb to normal levels if not a bit above.
Consensus of guidance seems reasonable over the weekend, while the
warmer MAV numbers look more realistic Monday.
Good radiational cooling is expected tonight and Sunday night. MOS
guidance seems to have a good handle on this, so did not deviate
much for lows. Sunday night should be a degree or two cooler on
average, due to a slightly drier airmass expected over the region.
.LONG TERM...(Monday Night through Saturday Night)
Issued at 324 AM CDT SAT AUG 2 2014
The forecast signal for the next period of convection still remains
consistent for onset next Thursday. There may be isolated convective
elements (isolated showers or thunderstorms) on the edges of the WFO
PAH forecast area Tuesday and Wednesday, but not enough to warrant
extensive discussion, given the model variability of PoP.
From Thursday onward through next Saturday, both the ECMWF and GFS
00z Saturday deterministic runs suggest that any defined ridging
behind the departure of the mean trough axis to the eastern seaboard
will be lacking in substance. Both models eject shortwaves from a
western U.S. trough across the Central and Northern Plain states,
breaking down a narrow amplitude shortwave ridge impacting the WFO
PAH forecast area. Initially most of the precipitation chances will
occur along the developing warm front and warm advection zone moving
in from the west late Thursday into Friday.
The WFO PAH forecast area will be poised along a west-east zonal
flow on the base of the faster westerlies, intermittent shortwaves
will ride along an impressed baroclinic zone (developing stationary
frontal boundary), supporting a prolonged period of isolated to
scattered convection into next weekend.
Issued at 1115 PM CDT FRI AUG 1 2014
The passage of a weak upper level wave will bring an increase in mid
level VFR cloudiness tonight. Showers and thunderstorms have largely
diminished through the evening, but a few stray showers remain. A
stray shower may impact KEVV and KOWB through the night, but will
not include mention at this time given anticipated minimal impact to
flight category. Patchy fog may briefly restrict visibilities at
KCGI and KPAH late tonight. Generally light and variable winds will
become northeast around 5 knots on Saturday.