Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Gaylord Michigan
653 am EDT Monday Mar 10 2014
issued at 251 am EDT Monday Mar 10 2014
A clipper system will pass north of Lake Superior this evening. We
will be on the warm side of the low...resulting in mild temperatures
today. An initial cold front moves across the area this evening...
with a second cold front arriving late Tuesday. Very cold air
settles in behind that front for Tuesday night into Wednesday night.
issued at 628 am EDT Monday Mar 10 2014
Best middle-level moisture and associated cloud cover...as seen on
Sat trends and as virga on radar...is diminishing from west to
east. Upstream Sat trends for northern lower are promising this
morning...with a small patch of middle clouds near grb...and then
some cirrus way back in northern Minnesota. So expect a healthy amount of
sunshine through midday (at least). We have that...increasing warm
advection at 925/850mb...and relatively mild temperatures to start the
morning (near or slightly below freezing). Current forecast maximum
temperatures allow for a 10-15f diurnal climb...but am thinking we/ll do
better than that. Will increase maximum temperatures a few degrees in
northern lower...perhaps only slightly in eastern upper where
cloud cover will be more prevalent. Have also fine-tuned cloud
cover trends today.
Short term...(today through tonight)
issued at 251 am EDT Monday Mar 10 2014
..warm day and more sprinkle/flurry action...
Currently, the surface trough in advance of the clipper system coming
out of northern Alberta is stretched out over the u p and Lake
Superior, putting north lower in the warm sector. The first impulse of
moisture and energy, is pushing through north lower, and with little
moisture in the lower levels, has produced little precipitation
except near anj during Sunday afternoon/early evening. Upstream,
there is another 500 mb speed maximum that is making its way through
Manitoba with the surface low and has an area of precipitation
associated with it. The concern for the short term part of the
package will be the precipitation chances.
Today...based on the precipitation trends from Canadian radar of the
upstream maximum/surface low, think that the GFS idea is too far south, so
will lean toward the RUC/NAM/ECMWF idea, that the morning will be
dry, until around 15z as the speed maximum pushes into c/east upper. The
lfq of the maximum looks to create the best lift in Ontario, not to
mention that there will be weak isentropic lift starting at the St.
Mary's River and north. So around 15z will allow for some sprinkles
or flurries around Whitefish pt. And areas downstream around the St.
Mary's. The rest of the forecast area should remain dry as the
upstream soundings show lots of dry air in the lowest 200 mb or so
of the atmosphere. By the afternoon, the speed maximum will be over NE
Lower/Lake Huron with the lfq lift in Canada entering the lower
Tonight...think that the GFS is still too fast with its bringing the
next system into the region (although south of the forecast area),
as the dry air that the European model (ecmwf) and NAM propose in the lower levels,
and looks like is the case when looking at the profiles upstream of
the Great Lakes. So will continue the dry forecast. Models show
little cold advection during the night with the west flow, so
temperatures seem in line with what would be expected.
Long term...(tuesday through sunday)
issued at 251 am EDT Monday Mar 10 2014
Our current fling with Spring will come to a screeching halt after
Tuesday...with sharply colder air invading for the middle-week period.
A well-advertised intensifying low pressure system will be moving up
the Ohio Valley in the same time frame. Will be keeping a wary eye on
it to ensure it doesn/T stray too far north. As long as it
behaves...the forecast is relatively quiet...with temperatures the main
Tuesday...we spend the day under a flat 500mb trough...with a Pacific
wave emerging from The Rockies into the Central High plains...and
Arctic energy digging into far northern Ontario. There is a paucity
of low level moisture in the morning...with weak mesoscale ridging
passing through. There will be a healthy amount of cirrus though...
especially in southern sections. In the afternoon...as colder air
settles in...a cumulus field should become more extensive...
especially in northern sections. Will remove chances for snow in
southern sections...as model soundings show abundantly dry air
present below 600mb (dew pt depressions 15-20c).
Cold advection is already in place to start the day...with 850mb
temperatures ranging from -7c in eastern upper to 0c by Saginaw Bay. Cold
advection gets boosted during the day as a secondary cold front
crosses eastern upper and moves into northern lower during the
afternoon. 850mb temperatures will tumble some 5-6c during the day. Partial
March sunshine will counteract this to some degree...and with a
relatively mild start maximum temperatures will look reasonable for the season.
Highs will be in the middle 30s to lower 40s...albeit somewhat early in
the day...with falling temperatures by late afternoon. Northwest winds will become
increasingly gusty...especially in eastern upper.
Tuesday night/Wed...surface low will move across the Ohio Valley and on
to Delaware-Maryland-Virginia. Partial phasing between the plains shortwave and Arctic
energy impinging on US will allow fgen and cold conveyor belt-
related precipitation to jump a bit northward. That said...all model
solutions still suggest this will...at absolute worst...just barely
clip our forecast area. Will continue with a small chance for snow
near/S of M-55 Tuesday night...and add it to the Gladwin/Tawas area
The main story is the bitter middle-winter airmass entering the region.
Said airmass is shallow...850mb temperatures tumble /only/ into the
middle/upper minus teens by Wednesday morning. But 925mb temperatures will be as
cold or colder...including -21c in eastern upper at daybreak off of
NAM soundings. This dry/shallow airmass should not be conducive to
getting any lake effect precipitation going...though a flurry or two may
not be completely out of the question (will not be including at this
time). A blanket of middle/high clouds will hold across most of
northern lower...starting to break down late Wednesday. Eastern
upper will have considerably less of that...and should have a
sunnier day Wednesday than places south of the bridge.
Guidance derived from the GFS would argue that the falling temperatures
that begin late Tuesday will last all of Tuesday night /and/ all day
Wednesday. That is a bit much...if only because partial March
sunshine should allow for a small diurnal bump Wednesday. Min temperatures
will range from near zero in eastern upper to the middle teens near
Saginaw Bay. Maximum temperatures will be in the teens.
Rest of the forecast...ridging will build overhead on Wednesday...
and the high cloud shield should depart. It continues to look like a
very cold night...with sub-zero mins across the forecast area...and
parts of eastern upper/far northern lower bottoming out close to
-15f. Weak warm advection begins Thursday as the high moves off...
and by Friday much of northern lower will take another run at 40f.
Said warm advection will also result in low-end precipitation chances Thursday
night into Friday night. But not to worry...another shot of cold air
arrives by the tail end of the weekend.
Aviation...(for the 12z tafs through 12z Tuesday morning)
issued at 653 am EDT Monday Mar 10 2014
Mostly VFR...outside of some morning fog at mbl.
Low pressure in central Manitoba will pass north of Superior late
today. Not a lot of moisture available south of this low...and
mainly just middle/high clouds expected. A touch of impacting mbl
this morning...that should mix out quickly after sunrise.
A west-southwest wind will be a touch breezy this afternoon...and will
lighten up tonight.