Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI
FXUS63 KMKX 192024
Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
325 PM CDT WED OCT 19 2016
.TONIGHT AND THURSDAY - Confidence...Medium.
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 shortwave passing to our south will induce
cyclogenesis that affects areas largely to our 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 the mention of some light rain in the far se corner with the
consensus of the ECMWF/GFS. The HRRR/RAP/NAM keep the nrn edge just
to our south but a close call. The 850 cold advection ramps up on
Thursday especially from late morning into the afternoon hours.
Meanwhile the 925 temps suggest low/mid 50s for highs with warmest
numbers in the far southeast.
.THURSDAY NIGHT THROUGH SATURDAY - Forecast Confidence...Medium
A quiet period is expected as short wave ridging passes through
the western Great Lakes Thursday night through Friday night.
Will continue to mention frost potential both nights but some
concern that clouds could linger across parts of the area
Thursday night due to nearby thermal trof. Both NAM and GFS
showing some lingering low level moisture in weakening low level
cold air advection. With 925H temps falling to around 0 to 2C
Thursday night, most areas should tumble into the 30s.
Clouds from upstream warm air advection may affect the area Friday
night, so again confidence not high on widespread frost potential.
Will however, include patchy frost as temperatures likely to fall
quickly in the evening. Southerly breezes and low level warming
should result in temperatures a few degrees warmer on Saturday
despite passing clouds.
SATURDAY NIGHT THROUGH WEDNESDAY - Forecast Confidence...Medium.
Amplifying short wave trof will move east across U.S./Canada border
and across the northern Great Lakes later in the weekend. Weak low
pressure surface reflection of passing wave expected to carry weak
cold front through southern WI late in the weekend, however ECMWF
and GFS not in very good agreement on timing and strength of cold
front attm. Never the less, do not expect any precip with frontal
passage due to dry atmosphere as deeper moisture remains cut off well
to the south.
Persistent long wave trof over eastern Pacific, off west coast, will
get nudged eastward early next week. This will result in quiet
weather continuing across southern WI at least through Tuesday as
long wave ridging moves across the area. This should result in
temperatures near or slightly above seasonal normal for late
October. Shower chances will increase Tuesday night into Wednesday
as south winds eventually pull deeper moisture into the area and low
pressure passes through the upper midwest.
GFS 5-day 500H means show above normal heights spreading into the
area early next week and lingering at least through mid-week.
Positive anomoly reaches 100meters at 00z/27.
.AVIATION/00Z 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 shortwave passing 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. So once we get into the CAA regime we will most likely
see some MVFR stratocu take shape but MOS and Bufkit are not
overly supportive of this. 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
.MARINE...North winds are expected to increase in the wake of a cold
front later tonight into Thursday. Some of the gusts may reach small
craft levels especially in the southern portion of the nearshore
area. This will also be in a region that will have higher waves due
to longest fetch. So will issue a small craft advisory for the
southern two nearshore zones from 12z Thursday through 08z Thursday
LM...Small Craft Advisory LMZ645-646 7 am CDT Thursday until 3
am CDT Friday.
TONIGHT AND THURSDAY/AVIATION/MARINE...COLLAR
THURSDAY NIGHT THROUGH WEDNESDAY...MBK