Area Forecast Discussion
Issued by NWS Louisville, KY
FXUS63 KLMK 300657
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
257 AM EDT Thu Jul 30 2015
.SHORT TERM (Now through Friday)...
Issued at 230 AM EDT Thu Jul 30 2015
A rather benign and seasonal period is in store for the Ohio Valley
through the next couple of days. A strong surface ridge will remain
in place, bringing mostly sunny skies and northerly winds today.
These northerly winds will usher in slightly cooler temperatures and
a much drier airmass. In fact, some areas may see dewpoints fall
into the upper 50s this afternoon during peak mixing, which will
feel quite nice given the high humidity values (dewpoints in the
mid/upper 70s) we`ve experienced over the past few days. Highs
today will be in the mid to upper 80s.
For tonight, skies will remain mostly clear and winds will go mostly
calm as surface ridging continues to nudge into the region. These
conditions should support a night of pretty good radiational
cooling. Therefore, will go on the lower end of guidance for low
temperatures which puts them in the low to mid 60s. Some of the
typically cooler spots may even dip into the 50s tonight!
Friday will nearly be a carbon copy of today. Mostly sunny skies
will persist with highs once again topping out in the mid and upper
80s, with the typically warm spots (the Louisville metro) pushing
towards 90. The good news is that dewpoints will once again be very
comfortable as readings will remain in the lower 60s.
.LONG TERM (Friday Night through Wednesday)...
Issued at 254 AM EDT Thu Jul 30 2015
As stated in previous discussions, the long term will be dominated
by a western ridge and eastern trof. This will keep our temperatures
from getting out of hand, but will make precipitation forecasts
tricky in the northwest flow regime. In general, though, Gulf and
Atlantic moisture will be suppressed to our south and east, and
Pacific moisture will remain to the north. With southern Indiana and
central Kentucky sitting in between these moisture sources, a drier
rather than wetter forecast is the way to go at this time.
On Saturday a weak cool front will sweep through. Will stick with a
dry forecast due to a lack of moisture in the column, the fact that
the front will be weak and getting weaker, and no obvious upper
shortwave trof to help spark storms.
There has been no run-to-run consistency within the GFS regarding
the passage of a cold front Monday night/Tuesday. The ECMWF has been
showing a steady trend of speeding up fropa, which is also what
happened in the days leading up to the fropa last night. So, will
introduce PoPs into Monday night and keep them going into Tuesday.
This front looks to be our best shot at rain during the long term.
In addition to slightly higher moisture availability, there will be
some upper level divergence to assist in convective development.
It looks like mid/upper flow will become more active next week so
will continue chance PoPs into Wednesday.
Highs each day will generally range from the mid 80s to lower 90s
with afternoon heat index readings not much worse than air
.AVIATION (06Z TAF Update)...
Updated 1250 AM EDT Thu Jul 30 2015
Despite some potential fog this morning, this TAF period will
feature VFR conditions. With lingering moisture around and skies
slowly beginning to clear out, there still does appear to be a
window for some fog development this morning mainly at KLEX and
KBWG. However, drier air working in from the northwest and the
lingering cloud cover should limit the threat enough to leave
prevailing vsbys in the MVFR range.
Otherwise, today will be a very pleasant, VFR day with mainly clear
skies and northerly winds around 10 knots.