Area Forecast Discussion
Issued by NWS Paducah, KY

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000
FXUS63 KPAH 240755
AFDPAH

Area Forecast Discussion
National Weather Service Paducah KY
255 AM CDT SUN JUL 24 2016

.SHORT TERM...(Today through Tuesday)
Issued at 255 AM CDT Sun Jul 24 2016

There is a little light at the end of the tunnel with respect to
the Excessive Heat Warning and Heat Advisory across the WFO PAH
forecast area. The next transition in the weather pattern will
take place today and tonight as heights and thicknesses associated
with the middle/upper level ridge shift east, while a similar
situation occurs over western Missouri and the Central Plains.

Amazingly, the Canadian Guidance, along with the GFS Ensemble, and
the NAM-WRF (NMM version) and the Central Region HRRR have a
fairly good handle on this transition. Feel better keeping minimal
PoP/Weather chances across the WFO PAH forecast area today and
tonight. The impressed closed low in the lower Mississippi Valley
will advect some moisture and instability into Southeast Missouri
this afternoon and evening, so kept a scattered convection
chances in that area. Otherwise, subsidence ahead of the
approaching frontal boundary in the northwest should limit any
significant southward transport with weak shear aloft. Any
extension well into the WFO PAH forecast area would have to come
from coordinated cold pool expansion of thunderstorm clusters
ahead of the slow moving cold front. Given the number of storm
mergers, dissipation and propagation along and ahead of slow
southward moving frontal boundary, a general 30 to 50 percent PoP
forecast was generated over the entire WFO PAH forecast area after
10 am Monday and extending over the remainder of the short term
forecast period.

Favorable conditions for fog generation will persist this morning
and again Monday morning, but the coverage and intensity should be
more intermittent in both time and space. For now, do not plan on
issuing any Dense Fog Advisories, but may submit a special weather
statement for those locations expecting more persistent fog
development.

Heat index values will be problematic on Monday, as moisture
pooling will keep dewpoints fairly steady state. The main
challenge will be any pockets of insolation (sunshine) that will
occur ahead of any overriding middle/upper level cloud shield.
Most heat index values should remain below 105 degrees. In
coordination and collaboration with surrounding NWS offices, plan
to let the current heat-related warnings and advisories expire
tonight at 8 pm CDT. Any mention of elevated heat index values
will be limited to the Hazardous Weather Outlook for Monday.

.LONG TERM...(Tuesday Night through Saturday)
Issued at 255 AM CDT Sun Jul 24 2016

Forecast confidence is high for the overall synoptic pattern
through the extended, but as usual the day to day details of
sensible weather will be tough to pin down.

The upper-level ridge will remain anchored over the Great Basin
throughout the extended portion of the forecast. As a result there
will be more troughing over the mid and upper Mississippi Valley and
Great Lakes. A series of relatively minor disturbances will stream
eastward over the region as the larger-scale trough develops. These
disturbances will likely support areas of convection generally
moving eastward across the region through the period. There is some
evidence especially in the 00Z GFS that a cold front may eventually
bring an end to this wet pattern next Saturday or Saturday night as
the primary upper-level trough moves eastward across the region.

The forecast will have a steady stream of chance PoPs through the
period, but higher PoPs will eventually become necessary. At this
time it is too difficult to try to pinpoint individual disturbances
and rounds of thunderstorms in time and space.

The primary concerns with thunderstorms next week will be locally
heavy rainfall and lightning. Some flooding issues may eventually
develop in areas that experience heavy rainfall from multiple areas
of thunderstorms through the week. A few severe storms cannot be
completely ruled out Thursday into Friday, as the flow aloft
increases a bit. If the GFS solution is correct, there may be a bit
better chance of severe weather on Saturday with the main upper
trough and the associated cold front.

Temperatures will start out just a bit above normal and end up near
normal levels, which will feel nice after the heat and humidity of
the last week or so.

&&

.AVIATION...
Issued at 613 PM CDT Sat Jul 23 2016

Could be some fog again overnight. Calm winds, and mainly clear
overnight. Some CU and high clouds Sunday with light south winds.


&&

.PAH Watches/Warnings/Advisories...
IL...Excessive Heat Warning until 8 PM CDT this evening for
     ILZ075>078-080>094.

MO...Excessive Heat Warning until 8 PM CDT this evening for MOZ076-
     086-087-100-107>112-114.

IN...Heat Advisory until 8 PM CDT this evening for INZ081-082-085>088.

KY...Excessive Heat Warning until 8 PM CDT this evening for
     KYZ001>009.

     Heat Advisory until 8 PM CDT this evening for KYZ010>022.

&&

$$

SHORT TERM...Smith
LONG TERM...DRS


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