Area Forecast Discussion
Issued by NWS Louisville, KY
FXUS63 KLMK 031650
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
1250 PM EDT Sun May 3 2015
...Updated Aviation Discussion...
.SHORT TERM (Now through Monday)...
Issued at 300 AM EDT Sun May 3 2015
3 AM surface analysis showed high pressure centered over North
Carolina, extending its reach from the Gulf Coast into the northeast
US. Aloft, water vapor imagery revealed a weak shortwave trough near
Chicago within an overall dirty zonal/weak northwest flow. Locally
across the lower Ohio Valley, readings were generally in the 50s.
Scattered high level cloudiness was spilling over southern Indiana
and northern Kentucky.
For today, another seasonably warm spring day is on tap for the
region. The aforementioned high pressure will drift off the NC
coast, resulting in weak southerly flow on the backside. Plan on
high temperatures to be roughly 3-5 degrees warmer than Saturday, so
most spots will top out in the upper 70s to low 80s. By afternoon,
look for few to scattered cumulus and dewpoints to mix out into the
low/mid 40s, keeping humidity levels in the comfortable range. Plan
on another mild and mostly clear night as readings fall into the mid
50s by early Monday morning.
Upper level ridging builds further on Monday across southeast US
into the lower Ohio Valley, which will act to hold a frontal
boundary to our north. This boundary lies up from southern Michigan
into central Illinois and Missouri. Will continue dry forecast and
given a bump in 850 mb temperatures, trended highs up a couple
degrees. Bias-corrected guidance puts the entire forecast area in
the low 80s and the typical warm, urban locations in the mid 80s.
South afternoon breezes around 10 mph can be expected under mostly
to partly sunny skies.
.LONG TERM (Monday Night through Saturday)...
Issued at 300 AM EDT Sun May 3 2015
A REX block with an upper level ridge centered over the Midwest
still looks to control the mid week forecast. With upper level
ridging in place solidly over the Ohio Valley Tues-Thurs, have gone
with a dry forecast. One could argue a dry forecast for Friday also
as ridging still looks pretty strong over the area with a slower
trend noted in forecast models of the ridge break down. However,
for consistency sake, will keep isld chances for convection Friday.
The GFS is the most optimistic with QPF Tues-Thu generating
afternoon precip each day. Think that the GFS QPF is overdone
overall, but it might have the right idea of perhaps an isld cell or
two bubbling up during the late afternoon or evening hours at or
just beyond peak heating. However, at this point, will stick with a
dry multi-model consensus for Tues-Thu.
The upper level ridge does start to break down by the end of the
week as the western coast upper trough makes progress inland. Upper
level shortwave activity will pass through the Ohio Valley as this
occurs resulting in better precip chances by the weekend (20-30%).
Temperatures will be above normal in the long term period with a
warming trend noted in the last few model runs for the end of the
long term period. Highs in the upper 70s/lower 80s are forecast for
Tue/Wed with highs solidly in the low to mid 80s for Thurs-Sat. Low
temps will range from the upper 50s to lower 60s.
.AVIATION (18Z TAF Update)...
Updated at 1249 PM EDT Sun May 3 2015
VFR conditions will persist at the TAF sites today. Scattered/broken
high clouds will continue to stream over the region and winds will
remain out of S/SW. Another night of light winds and mostly clear
skies could result in light, shallow fog again at BWG during the
pre-dawn hours Monday. Otherwise, Monday will be similar today
with WSW winds and just some passing mid/high clouds.