Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
FXUS63 KMKX 191558
Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
1058 AM CDT WED OCT 19 2016
.AVIATION/18Z TAFS/...Mid level moisture continues to stream into
the area in assoc with stg wsw 500-300 millibar flow. Cold front
proggd to drop to our southeast this evening and switch winds
around to the north into Thursday. A 500 millibar shortwavepassing
to our south will induce cyclogenesis that affects areas largely
tour southeast though the GFS and ECMWF does clip our far
southeast with precip. Bufkit soundings do show primarily mid
level saturation so moisture profile not the most conducive for
much of this reaching the ground. Will leave a mention in the far
se corner with the consensus of the ECMWF/GFS. The NAM keeps
things dry in the southeast corner. So once we get into the CAA
regime we will most likely see some MVFR stratocu take shape. The
NAM looks a little too moist in the BL. LLVL RH progs show a
better intrusion of a potential stratus/stratocu deck with the
arrival of the colder 850 temps after 18z Thursday.
.MARINE...Expect offshore winds to turn more north to northeast
today as low pressure begins to develop on a frontal boundary
situated well south of the Great Lakes. Atwater Buoy measuring a
lake surface temperature in the 40s as the offshore winds have
resulted in cool upwelling...while mid-lake surface water temps
remain in the lower 60s.
There is a small chance a few showers could affect areas south of
North Point Light tonight as the low pressure area moves through
the TN and OH Valleys. Otherwise, a tightening pressure gradient
associated with this low pressure area will result in increasing
north winds late tonight and Thursday. Wind gusts will approach
Small Craft Advisory levels for a time.
.PREV DISCUSSION... /Issued 309 AM CDT WED OCT 19 2016/
TODAY AND TONIGHT...Forecast Confidence Is Medium.
A strong west/southwest upper jet across Wisconsin becomes a little
more southwest as an upper trough begins to dig across the northern
and central plains. Southern Wisconsin is in the entrance region of
the 120 knot 250 mb jet by sunrise Thursday. Some weak upper level
divergence and 700mb upward motion tonight. 700 mb RH increases
mainly far southeast just after midnight, before drying again.
Surface winds do become north, but think the slight chance of
showers would be mid level based, but even those should be mainly
Expect increasing high/mid clouds today and especially tonight.
THURSDAY THROUGH SATURDAY...Forecast Confidence...Medium
A wave will move through early Thursday, but with very little
moisture to work with, so left the forecast dry. High pressure
will be building in through the day Thursday as the wave exits,
with the high remaining in the region through Saturday.
Temperatures will be a couple/few degrees below normal for
Thursday and Friday behind the departing low, warming back to
around normal Saturday.
SUNDAY THROUGH TUESDAY...Forecast Confidence...Medium
Low pressure is progged to move through Sunday. It currently looks
like the best forcing will remain to the north of the forecast
area, so expecting the dry weather to continue. High pressure will
follow the departing low for Monday.
A stronger low will develop to the west on Tuesday, with deeper
moisture moving in ahead of the low by later in the day. Certainly
some differences between the ECMWF and GFS this far out, but
enough agreement at this point for some chance pops.
Temps will be near to a couple degrees above normal for the first
couple days of next week.
Isolated MVFR/IFR in low areas trough sunrise mainly in low areas
and river valleys. otherwise VFR conditions expected.
Increasing moisture will bring high and then mid-level clouds today
and especially tonight.
High pressure today will weaken. light winds becoming more
east/north tonight. Will still be looking at winds/wave heights
increasing late tonight then approaching or reaching Small Craft
Advisory levels Thursday/Thursday night as north winds increase with
the tightening gradient, between low pressure lifting up the Ohio
River Valley, and broad high pressure building in from the Plains.
TODAY/TONIGHT AND AVIATION/MARINE...Hentz
Thursday THROUGH Tuesday...DDV