HAMweather.com Area Forecast Discussion for County Warning Area LMK

Thu, 16 Feb 2012 07:45:40 GMT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
1234 AM EST THU FEB 16 2012

.Update...
Issued at 1230 AM EST Feb 16 2012

An initial batch of more moderate rain has moved through the western
portion of the forecast area this evening. Showers continue to
develop to the west of this initial batch of rain, but are a bit
more scattered in nature. With the development of a LLJ over the
next couple of hours, a lightning strike or two is not out of the
question so will leave isolated wording in the grids. Updates were
mainly to match current trends.

Issued at 950 PM EST Feb 15 2012

Moderate rain showers have pushed into our northwest forecast area.
The bulk of the precip will impact our northern and western CWA
through the next few hours before overspreading the entire forecast
area. Have adjusted PoPs to reflect the best activity. Temperatures
have been fluctuating with the onset of precipitation. So, have made
subtle changes to temps as well.

Update issued at 600 PM EST Feb 15 2012

Rain showers are starting to increase in areal coverage across the
region, with a decent area of rain headed our way from western
Kentucky. Have adjusted PoPs for the next few hours based on current
radar trends and blended into the overnight period. This really only
impacts the web and hourly products. These have been updated. Will
continue to adjust as necessary through the evening.

.Short Term (Tonight through Thursday night)...
Updated at 300 PM EST Feb 15 2012

A weakening upper wave over the Red River Valley this evening will
push to the east tonight, cross over the LMK CWA Thursday morning,
and continue on to the east.  An area of showers will surge ahead of
this wave and move through central Kentucky and southern Indiana,
particularly from midnight tonight into early Thursday morning.  A
low level jet will crank up tonight, plus there has been some
thunder upstream today, so will continue the chance of isolated
rumbles of thunder after midnight. Heavy rain is not expected
though, with event totals in the one third to one half inch range.

The last showers will exit the Blue Grass around lunch time
tomorrow, with high pressure building in from the west providing us
with dry weather Thursday afternoon and night.

Current thinking is that temperatures will not fall very much
tonight ahead of the approaching storm system, with lows ranging
from the mid 40s in southern Indiana to around 50 along the
Tennessee border.  Temperatures tomorrow won't rise much with
morning rain and clouds all day, so will keep readings in the 50s
with cold air staying to our north and zonal flow aloft.  The
surface high, along with partially clearing skies, will allow
temperatures to fall Thursday night however, down to around the
freezing mark (which is normal for this time of year).

.Long Term (Friday through Wednesday)...
Updated at 300 PM EST Feb 15 2012

Friday through Saturday...

Surface high pressure will be in control with zonal flow aloft
Friday through Saturday. Expect mostly clear skies Friday with
increasing upper level sky cover on Saturday. Have continued the
trend of keeping Saturday dry across the south as models continue
are having trouble with ejection of southwest CONUS energy and the
potential phase with the northern stream. GFS is the outlier today
and like the consistent forecast of a dry Saturday that has been
ongoing. Have trended highs for Friday up just a bit with most
locations topping out in the low 50s. Expect to see lows right
around the freezing mark in most spots Friday night, with a few
upper 20s in the coolest spots. Will continue with highs right
around 50 for Saturday with increasing sky cover and light cool air
advection commencing as surface low across the Gulf Coast states
ramps up.

Saturday Night and Sunday...

The biggest question over the weekend still remains with model
uncertainty in how ejecting SW CONUS energy across the Gulf Coast
states interacts with northern stream. Potential phase suggested by
GFS would allow for stronger low development, and more moisture
northward into our CWA. With temperatures falling into the lower 30s
Saturday night, would likely see rain changing to snow. Will
continue small chances for rain or snow Saturday night mainly across
the south and east. Still think this is eventually going to be a dry
forecast, however feel persistence is the best way to go until
models work themselves out. Low chances linger in the east on Sunday
with low moving off the Carolina Coast. Look for highs on Sunday
only in the low to mid 40s.

Sunday Night - Monday...

Brief and strong ridging aloft will continue through at least Monday
with surface high pressure in place. Dry weather will prevail with
temperatures warming into the mid 40s to around 50.

Monday Night - Wednesday...

Chances for rain showers look to enter the forecast again as early
as Monday night but more likely by late Tuesday and Wednesday. Will
go with low chances for light rain showers with highs in the low to
mid 50s.

.Aviation (06Z TAF Issuance)...
Updated at 1150 PM EST Feb 15 2012

Showers are widespread across the forecast area as of 05Z. These
showers will continue at all sites over the next few hours. They
should then begin to taper off at BWG and SDF during the early
morning hours and at LEX by mid morning. Despite showers tapering
off, a low stratus deck will hang around through the morning hours
and into the early afternoon. Ceilings should then begin to clear
from the west with VFR conditions and light winds expected tonight.

Winds are fairly light right now and will continue to be until the
front moves through. This front will shift winds to the WSW and then
to the WNW during the day today. Speeds will increase to around
10-12 knots in the wake of the front. Models continue to indicate a
LLJ will develop over the next couple of hours. The latest guidance
suggests this will main affect LEX and BWG so have removed wind
shear wording from SDF. However, will continue to monitor this
overnight.

.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.