Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Wilmington Ohio
144 am EDT Tuesday may 26 2015
our region will be underneath moist southwest flow aloft through
middle week. Embedded disturbances will interact with this moisture to
bring the threat for showers and thunderstorms.
Near term /until 6 am this morning/...
highly amplified middle/upper level flow with a ridge over the East Coast
and trough over the nations middle section. This places the Ohio Valley in
a moist southerly flow. An embedded middle level shortwave to pass to
the NE with all precipitation coming to a temporary end overnight. Have
diminished probability of precipitation to account for this lull.
Considerable cloudiness expected and with southerly winds staying
up around 10 miles per hour...temperatures will remain mild overnight.
Expect lows generally in the middle and upper 60s.
Very strong low level jet this morning allowed a swath of light
rain to form over the western parts of the County Warning Area with most of the
central and eastern parts remaining dry. The nose of the low level jet has
started to push towards the northeast allowing the light rain to
slowly dissipate as the best surface convergence moves out of the
area. Winds have also started to come down a bit as the low level jet exits.
The atmosphere remains moist with precipitable waters currently around 1.60"
according to gpsmet. Have continued thinking though of there being
a break in the rain this evening into Tuesday morning as the area
lies in the wake of a shortwave off to our northwest. Low
temperatures will again be very warm for this time of year with
temperatures expected to be in the middle to upper 60s Tuesday morning.
Short term /6 am this morning through Wednesday night/...
rain will remain in the forecast Tuesday afternoon as another
shortwave rotates around a quasi- stationary low over The Rockies.
The shortwave can be currently seen on infrared over central Texas. This
shortwave will finally dislodge the low over The Rockies. Precipitable waters
Tuesday are forecasted to be up as high as 1.80" along with a
tail of the upper level jet approaching (rrq). Instability wise
the GFS and NAM have cape values ranging from 700 to 1200 j/kg.
The NAM also has a pretty good wedge of dry air in the 600 to
700 mb range. This signal in the GFS is much more muted though.
Surface Delta Theta- east on the NAM is approaching 30 in the
afternoon. Storm Prediction Center has also continued the slight risk across our area.
With the dry air forecasted in the middle levels damaging winds will
be the main threat Tuesday. Will continue to indicate a low threat
for severe in the severe weather potential statement.
Tuesday night the leftover remnants of the upper level low will
approach from the west. Convection looks to continue through
Wednesday as instability... upper level lift... and moisture all
linger across the area. As various shortwaves move over the area
there will be break periods in the rain as weak upper level
convergence is usually expected on the back side of each
shortwave. Given the difficult nature of timing each individual
shortwave have kept chance/ likely probability of precipitation through Wednesday.
Long term /Thursday through Monday/...
our area will be on the northwest side of an area of high pressure
situated across the southeastern United States on Thursday. This
will allow for a continuation of southwesterly low level flow with
high temperatures pushing up into the lower 80s through the
afternoon. With the combination of some destabilization and some
possible middle level vorticity energy...will continue with a 20-30 pop on
Middle/upper level flow will become more amplified through the weekend
as short wave energy moves out of The Rockies and into the Central
Plains. This will eventually lead to a frontal boundary pushing down
toward and possibly through our forecast area through early next week.
However...there remains quite a bit of difference between the
European model (ecmwf)/GFS/CMC with how fast and how far south to push the front and
whether or not to stall it out across our area toward the end of the
period. This will lead to the potential for a fairly wet/more active
period through the end of the long term but due to the timing
uncertainties...will just keep probability of precipitation in the high chance category.
Friday will be seasonably warm with highs in the middle 80s. More
seasonable temperatures will then begin to push down from the north
over the weekend...but they will ultimately be dictated by the
placement/timing of the frontal boundary. For that reason...have
generally gone with a model blend for temperatures Saturday through
Aviation /06z Tuesday through Saturday/...
first concern early this morning is the potential for MVFR
ceilings and visibilities. Am getting mixed signals for MVFR
ceilings per latest models. However...there are some lower clouds
developing near kcvg and kday...and these may become a ceiling
around 2000 feet over the next 4 hours...about 2 hours later at
kcmh and klck. Visibilities should be held in check given surface
pressure gradient...Sans kluk which may drop into the 3-5sm range.
For later today...our region will be underneath a moist southwest
flow aloft. Morning daytime heating will result in cumulus
development with winds picking up from the south. By the
afternoon hours...a disturbance will rotate northeast into the
western Great Lakes. A trailing tail/inflection in the middle levels
will team up with a potential low level convergent axis to bring
the likelihood of showers and thunderstorms. There continues to be
some timing and coverage issues with the high resolution models so
have opted to keep thunderstorms in the vicinity going at this time. Will attempt to pick
a tempo group for the best chance at the terminals with the next
taf issuance. Otherwise...with the moist airmass in place...MVFR
conditions will be likely with storms with local pockets of IFR
conditions (most likely visibilities) due to heavy rainfall in the
For tonight...disturbance and its tail/inflection will push off to
the northeast through the remainder of our region. With the loss
of daytime heating...we should see a gradual decrease in
thunderstorm activity...with just a few showers lingering in the
moist flow late tonight. Models suggest that some MVFR/IFR ceilings
may develop in the 06z to 12z and will take a look at this again
with the next issuance.
Outlook...MVFR/IFR ceilings possible Wednesday morning. Thunderstorms
possible Wednesday afternoon and evening...and again Saturday.