Area forecast discussion
National Weather Service Marquette Michigan
736 am EDT Wednesday may 22 2013
Short term...(today and tonight)
issued at 521 am EDT Wednesday may 22 2013
Dry air will be slowly edging southeast across Lake Superior and Upper Michigan
over the next 24 hours. Taking a look at the 00z sounds from cwpl
and kgrb...they were of very different airmasses. The larger weather
pattern looks like this...a large 500mb ridge stretching from
central Canada through east Montana a and into Colorado...with a north stream low set
up over eastern Hudson Bay and north Quebec...and the nearly steady
state 500mb low spinning across S Minnesota and Iowa. The large surface low
stretching from Iowa through Illinois/Lake Michigan/lower Michigan and Lake Huron will
continue to slowly push eastward.
The axis of stronger fgen has been productive in producing a few
showers...but with not much amplification. As a result...slightly
lower precipitation amounts were needed through at least the morning hours.
As this area shifts southeast during the day today through tonight. At this
point...the best chance of accumulating precipitation at or above a tenth
of an inch will fall over the far west this morning...and then sink
to S central Upper Michigan this evening. With the favorable NE upslope
winds just above the surface...could not rule out some lake enhanced
showers or drizzle over north central Upper Michigan 00-06z Thursday. Fog will
be the main threat...slowly diminishing north to S as drier air works
in. Expect dew points in the 40s to middle 50s this morning to fall
into the 30s northwest to southeast tonight.
While the surface low will shift from lower Michigan through the lower Great
Lakes tonight...its influence on our weather will remain. The
strengthening pressure gradient between the exiting low and nearing
high from northern Canada will result in increasing NE-north-northeast winds to
the region...with gusts 20-25kts over all but far west Upper Michigan
overnight. 850mb temperatures will fall to -1 to 3c /lowest west/ by daybreak
Thursday...with surface temperatures under diminishing cloud cover...falling
into the upper 30s west and central. We Haven/T seen lows in the 30s
for much of the County Warning Area in approx 5 days...so it will be a bit of a
change.
Long term...(thursday through tuesday)
issued at 407 am EDT Wednesday may 22 2013
A closed 500 mb low will be in the Pacific northwest with a trough over the
Great Lakes region and a ridge across the plains 12z Thursday. Pattern
changes little this forecast period with the trough over the Great
Lakes moving to the eastern U.S. 12z Sat and the ridge staying put
in the plains. Looks dry for this forecast period with cold
temperatures. There will be some frost for Thursday night and Friday night
and put it in the weather grids to help with the fire weather
forecast. The frost/freeze season starts after Memorial Day...but
will mention this in the severe weather potential statement product. With the ridge nearby and very
dry and cold air...good radiational cooling conditions will set up
and went with the coldest guidance I could find for low temperatures
which was the adjmet and made a few adjustments for colder spots.
Highs on Thursday will struggle to get to the middle 50s. For Friday...went
colder for highs as well with a colder start in the morning and 850
mb temperatures warming only to 4c. Mixing this down to the surface
would give ME highs around 60 at best. The temperatures were the
main thing that I adjusted for this forecast with a slightly colder
forecast.
In the extended...European model (ecmwf) and GFS show a 500 mb ridge across the
plains with troughing in the Pacific northwest and in New England 12z Sat.
Pattern changes very little 12z sun through 12z Tuesday. Will be fairly
dry this forecast period and quiet with colder than normal
temperatures with a slow warming trend through the period. There is
a slight chance for precipitation Monday night and Tuesday with a warm front
setting up to the south...but not real impressed with seeing much
rain out of this for now.
&&
Aviation...(for the 12z tafs through 12z Thursday morning)
issued at 736 am EDT Wednesday may 22 2013
Expect -shra/-dz at times...especially at kiwd/kcmx due to their
location in relation to an area of more persistent synoptic forcing.
These more persistent -shra should drift southeast and affect ksaw this
afternoon. Dry high pressure to our northwest will slowly bring clearing
conditions overnight...with VFR conditions expected at all 3 taf
sites by or shortly after 00z Thursday.
&&
Marine...(for the 4 am Lake Superior forecast issuance)
issued at 407 am EDT Wednesday may 22 2013
Arrival of drier air from the northwest today will slowly diminish the fog
on the Great Lakes. Gusty northerly winds are expected behind the
low pressure system tonight into Thursday...but lingering warm air
aloft should keep winds in 20-25kt range. Then...a high pressure
ridge building southeast over the upper Great Lakes for Thursday
night through the weekend will bring light winds to Lake Superior.
&&
MQT watches/warnings/advisories...
Upper Michigan...
none.
Lake Superior...
dense fog advisory until 5 PM EDT this afternoon for lsz249>251-
266-267.
Dense fog advisory until 2 PM EDT /1 PM CDT/ this afternoon for
lsz162-240>242-245>248-263-265.
Dense fog advisory until 8 am EDT this morning for lsz243-244-
264.
Lake Michigan...
dense fog advisory until 2 PM EDT this afternoon for lmz221-248.
Dense fog advisory until 6 PM EDT this evening for lmz250.
&&
$$
Short term...kf
long term...07
aviation...kf
marine...07
