Area Forecast Discussion
Issued by NWS Louisville, KY
FXUS63 KLMK 251337
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
937 AM EDT Mon Aug 25 2014
Issued at 930 AM EDT Mon Aug 25 2014
Last of the early morning fog and stratus now burning off over
south-central and east-central Kentucky. A lot more sunshine already
this morning compared to 24 hrs ago, so really not seeing any reason
we won`t match yesterday`s max temps. Have bumped this afternoon`s
highs accordingly, with most areas just either side of 90, and
borderline oppressive humidity pushing heat indices into the upper
Still could see afternoon pop-ups, mainly in the southern/eastern
sections of the CWA. Current 20 POP may cover a bit too much area,
but we`ll revisit this in an hour or two.
.SHORT TERM (Now through Tuesday)...
Issued at 325 AM EDT Mon Aug 25 2014
Morning satellite and surface observations reveal mainly clear skies
across the forecast area. Some patchy fog was evident in the
typical low-lying and fog prone locations. NWS ASOS and Kentucky
Mesonet observations reveal readings generally in the lower 70s.
Expect mainly clear skies to continue through the early morning
hours. Some low stratus may pull up into the Lake Cumberland region
later this morning from the Tennessee plateau region. Overnight
minimums will generally be in the lower 70s.
For Today/Tonight, the short term multi-model consensus continues to
be in agreement with a rather large deep layer ridge holding across
the region. The higher resolution models do suggest that a surface
convergence will develop later this afternoon near the I-75
corridor. This may result in some isolated convection developing in
the afternoon hours. Overall coverage looks to be quite sparse
(generally 20% or less). Afternoon temperatures will warm into the
upper 80s in the east with upper 80s to around 90 in the west. These
temperatures combined with dewpoints in the 70s will make it feel
more like the mid-upper 90s. Skies are expected to clear back out
tonight with some patchy fog once again developing in the low-lying
and typical fog prone areas. Overnight lows look to cool into the
lower 70s once again.
For Tuesday, deep layer upper ridge will continue to hold sway
across the region. With the increasing heights and mid-level
warming, expect more of a cap across the region on Tuesday keeping
convection quite sparse across the area. Overall coverage at this
time looks to be 10% or less. Temperatures will remain quite warm
with upper 80s to around 90.
.LONG TERM (Tuesday Night through Sunday)...
Issued at 300 AM EDT Mon Aug 25 2014
.Tuesday night through Thursday...
The early to mid portion of this upcoming work week will feature
broad ridging across the southern tier of states, centered over the
Gulf States and the Lower Mississippi Valley. Cristobal, either as a
tropical storm or a hurricane will move north and then northeast
well east of the mid-Atlantic coast. Farther north, a positively
tilted shortwave and low pressure center north of New England will
trail a cold front that will stall and dissipate somewhere near the
Lower Ohio Valley early Thursday.
Expect hot and humid weather Wednesday and Thursday. However both
dewpoints and precipitable water will fall to values more typical of
late August; the tropical airmass that had been in place over the
weekend will be a thing of the past. Both the NAM and the GFS sag a
weakening front south towards southern Indiana late Wednesday. This
may serve as a trigger for some isolated to scattered thunderstorms
late in the day or evening across our northern counties. This
boundary will largely dissipate by Thursday, although again some
isolated thunderstorms may develop during the afternoon or evening.
Both days will stay quite warm, with highs in the lower 90s and lows
falling into the upper 60s to the lower 70s. Winds will be quite
light over this period, with calm winds at night.
.Friday through Sunday...
The early portion of the weekend will feature flat zonal 500mb flow
along the northern tier of states. A shallow shortwave trough will
however, slowly begin to eject eastward of the Rockies. By
Saturday, this is forecast to lie over the southern plains. This system
will serve as a focus for widespread convection Friday and Saturday
across the Lower Missouri Valley, extending northeastward across
the southern Great Lakes. Initially, the Lower Ohio Valley will be
too far east to see anything more than typical summer-time isolated
afternoon and evening storms through Saturday. By Sunday however,
scattered to even numerous storms may develop as this sheared out
shortwave sags southeast and moisture begins to pool along the Ohio
River. Both Sunday and Monday will offer several chances for
additional rainfall. Temperatures will stay several degrees above
normal for late August, with daytime highs reaching the upper 80s to
the lower 90s.
.AVIATION (12Z TAF Update)...
Issued at 640 AM EDT Mon Aug 25 2014
Upper level ridging will continue to build across the region through
the upcoming TAF period. This is expected to result in benign
weather conditions at the terminals. Some patchy fog will be
possible this morning in the typical low-lying and fog prone areas,
but it should mix out quickly after sunrise. Otherwise, VFR
conditions are expected through the upcoming period. Some isolated
convection may develop across portions of south-central and
east-central KY this afternoon which could include the KLEX
terminal. At this time, coverage looks too sparse to warrant a
mention in the upcoming TAF at this time.