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Area forecast discussion 
National Weather Service Milwaukee/Sullivan WI
1022 am CDT sun Jul 5 2015

Aviation/18z tafs/...quiet and VFR for much of this period.
Southerly flow gradually picks up ahead of frontal boundary
approaching from the plains. May see patchy fog develop once
again tonight but not expecting anything too widespread or dense
as south winds aloft will be a bit stronger. Still looks like the
main line of storms arrives later Monday afternoon with the best
likelihood Monday night. Models are hinting at some pre-frontal
development late morning/Erly afternoon but the main event looks to be
Monday night.

Pc

&&

Marine...shoreline web cams indicate light haze over the nearshore
waters extending into the open waters of the lake. Winds have
already begun to turn onshore and south to southeast winds will
persist through tonight. Recent modis imagery measured lake surface
temperatures in the lower 60s...which will be close to expected surface dewpoints
today. Hence pulled fog mention but think areas of light haze will
continue. Tightening pressure gradient ahead of approaching cold
front and insolation will allow gusty south winds to affect near
shore area on Monday. Small Craft Advisory still looking likely.

Mbk

&&

Previous discussion... /issued 333 am CDT sun Jul 5 2015/

Today and tonight...forecast confidence...high

Very weak 250 mb flow with a ridge to the north and trough well
south. Little or no 700 mb upward motion.

Very weak 850/700 mb warming later today and tonight. 700 mb levels
are dry. 850 mb dew points increase late tonight over south central
Wisconsin.

Forecast soundings have a fairly strong cap above 850 mb with an
extensive dry layer above. Therefore the 1000 joules/kg of cape
mainly southwest of Madison this afternoon will not come into play.
Only a few fair weather cumulus expected.

With the surface high centered over the eastern Great Lakes to the
Ohio and Tennessee Valley...the light south flow will continue
this morning and increase slowly. Hrrr wind gust increase to
around 15 miles per hour this afternoon...and around 20 miles per hour along Lake
Michigan. As the pressure gradient tightens tonight winds should
not decouple much...but still should be mainly around 10 miles per hour.
Expect a lake breeze to develop but not progress as much inland.

Surface dewpoints should be in the lower 60s this morning and
increase to the middle 60s later this afternoon. With the strong cap
mixing will be somewhat limited.

Monday...forecast confidence...medium

Models remain in pretty good agreement with the timing of a low
pressure system and associated cold front on Monday. Should be a
good increase in moisture ahead of the front...with the GFS and
NAM increasing precipitable water values to around 2-2.25 inches.
Cape values...0-6 km bulk shear...and middle level lapse rates not
particularly impressive. Some stronger storms possible though given
the front timing along with respectable lower level shear and
lapse rates. Storm Prediction Center has maintained the forecast area under a marginal
risk for severe storms. Overall...looks like a decent chance for a
round of afternoon and evening Summer storms...so bumped probability of precipitation up
some more.

Still thinking it will be a warm day Monday...with 925 mb temperatures of
22-25c ahead of the approaching front. Main concern is that
upstream convection from Sunday night might limp and cloud things
up early. Some models also have storms firing earlier in the day
before main line of storm with front moves in. Though these are
possibilities...do think there will be enough sun for forecast
highs. Looks breezy for much of the day as well ahead of the
approaching front.

Tuesday through Saturday...forecast confidence...medium

Any lingering precipitation should wind down in the southeast by early
Tuesday morning...with dry weather then expected though at least
Thursday morning under high pressure. Have some probability of precipitation in for later
Thursday through Saturday...as models showing a couple waves to
move through the area. Not great agreement in wave placement and
timing between models...so chance probability of precipitation are spread out through this
period.

Models have at least come into better agreement with temperature
trends for the extended. Generally looks like below normal temperatures
behind the departing cold front through at least mid-week...with
temperatures returning to around normal by the weekend.

Aviation/12z tafs/...

VFR conditions expected today and tonight. Elevated smoke layer from
the Canadian Forest fires will continue today.

Forecast soundings have a fairly strong cap above 850 mb with an
extensive dry layer above. Only a few fair weather cumulus expected.

With the surface high centered over the eastern Great Lakes to the
Ohio and Tennessee Valley...the light south flow will continue
this morning and increase slowly. Hrrr wind gust increase to
around 15 miles per hour this afternoon...and around 20 miles per hour along Lake
Michigan. As the pressure gradient tightens tonight winds should
not decouple much...but still should be mainly around 10 miles per hour.

Marine...

With the surface high centered over the eastern Great Lakes to the
Ohio and Tennessee Valley...the light south flow will continue
this morning and increase slowly. South/southeast wind gusts
increase to around 20 knots this afternoon. As the pressure
gradient tightens tonight winds should not decrease much...but
still should be mainly just below small craft criteria through
tonight...but may be needed Monday.

As dew points rise fog may become more of an issue...so will include
patchy fog for now today.

&&

Mkx watches/warnings/advisories...
WI...none.
Lm...none.
&&

$$
Today/tonight and aviation/marine...hentz
Monday through Saturday...ddv

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