Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Jackson Kentucky
947 PM EDT Monday Mar 10 2014
issued at 947 PM EDT Monday Mar 10 2014
Forecast was still on track based on observation data from the past few hours
and latest models. Conditions will remain conducive to a well defined
Ridge Valley temperature split for most of the area tonight. Some
indications of the split are already showing up in the observation...with the
mesonet sites at Paintsville and quicksand reading 46 and 47 degrees
respectively as of 945...with much warmer readings in the middle to
upper 50s at surrounding stations. Winds will be light in valleys
tonight...with southwest flow around 5kts on the ridges. The forecast
text was updated to removed outdated evening wording. Aside from
that...no other changes were necessary.
Update issued at 743 PM EDT Monday Mar 10 2014
The forecast was right on track this evening. Surface observations
around the area indicate that winds that were quite brisk and gusty
this afternoon have subsided now that the sun has begun to go down.
Temperatures were also on track. It looks like we will be in for
nothing more than a smattering of high clouds this and tonight. With
the wording in the existing zone forecast text product also in good
shape...no update was deemed necessary at this time.
Short term...(this evening through Tuesday night)
issued at 400 PM EDT Monday Mar 10 2014
Quiet weather will continue through Tuesday. Surface high pressure
was located well to our south this afternoon...as a cold front was
dropping south through the Midwest...but was still well to the north
of the Ohio River. Wind flow between the two was bringing warm air
advection for the local area...but moisture return has still been
meager. This scenario will hold into Tuesday night...as the front
progresses to near the Ohio River.
An area of low pressure will move east along the front...and rapidly
deepen as it progresses up the Ohio Valley Tuesday night. Gulf
moisture will finally be drawn north in the warm air advection.
Models have backed off considerably on the quantitative precipitation forecast for Tuesday night.
Showers still appear to be a good bet...but in light of the 12z
models...have gone with slightly lower probability of precipitation than in the previous
forecast. Weak elevated instability is still present in forecast
soundings Tuesday night...and will use a slight chance of thunder.
For temperatures...conditions are favorable for substantial Ridge/Valley
differences again tonight. This should be much less prevalent on
Tuesday night as clouds and winds increase. However...there still may
be a time window in the evening in which valleys could decouple and
start to see temperatures drop off.
Long term...(wednesday through monday)
issued at 400 PM EDT Monday Mar 10 2014
Most of the impactful weather will be on the front end of the
extended forecast today as a potent storm system pushes across the
area Wednesday into Wednesday night. Models are in reasonable
agreement with this system...so confidence is fairly good with this
storm. A surface low will track from near Louisville Wednesday
morning...into northern West Virginia by midday...and finally into
the Middle Atlantic States by the evening. This will take the surface
low just north of eastern Kentucky...placing the area in the warm
sector through the early portion of Wednesday. As good upper level
dynamics overspread the area Wednesday morning we should see
showers...and perhaps some thunderstorms spread across the area.
With the surface low so close to the area by midday...we could get
dry slotted...providing for more of a drizzle as we head into the
afternoon hours. However...as the surface low pulls east in the
afternoon and evening...it will drag an Arctic cold front south.
This will set the stage for sharply falling temperatures through the
afternoon and evening. In addition...strong...gusty winds gusting up
to 40 or 45 miles per hour will be possible. Some wind headlines will likely be
needed on Wednesday to account for these winds.
The next threat will come in the form of snow. As the cold advection
brings temperatures downward...we will have a deformation axis push
across the area...providing deeper moisture. This will introduce ice
back into the clouds...providing a period of snow showers for
eastern Kentucky from late afternoon well into the evening and
overnight hours. Lapse rates are not overly impressive...but given
the strong cold air advection...and tight gradient...we could see
snow squalls develop and produce whiteout conditions at times. With
the expected changeover expected to occur near the evening
commute...a Winter Weather Advisory may need to be considered for
the potential impacts. Snowfall amounts are not expected to be all
that impressive with the ridges likely seeing the highest totals
just over an inch and valley locations staying under an inch. The
snow will obviously be helped out by upslope flow through the
evening. As the deeper moisture departs...we should see the strength
of the snow showers weaken into the overnight hours...eventually
tapering off to flurries late. Lows will crater through the
overnight hours into the teens by daybreak Thursday. Clouds may
persist longer into Thursday than models anticipate given the
thermal ridge is still out to our west during the day.
The ridging will eventually spread east late in the week...allowing
for temperatures to moderate as we head into Friday and the upcoming
weekend. Another storm system will then take aim on the area late
Sunday into early next week...but details surrounding the
track...strength of this system are very much in question.
Confidence beyond Saturday remains very low.
Aviation...(for the 00z tafs through 00z Tuesday evening)
issued at 743 PM EDT Monday Mar 10 2014
The taf period will feature VFR conditions with scattered high clouds
and light winds.