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Area forecast discussion 
National Weather Service quadrant cities Iowa Illinois
542 PM CST Sat Nov 28 2015

issued at 253 PM CST Sat Nov 28 2015

The region remains on the fringe of a deep plume of
moisture and warm advection aloft that extended over the southern
2/3rds of the Continental U.S.. this has left our north in and out of the middle
clouds...with just a touch of sun that has not brought much from day
time heating. The south is deeper into the moisture...and has
squeezed out a few sprinkles in a narrow band of light showers that
has moved up to around Burlington as of 2 PM. Temperatures are above
freezing in the south...and may remain that way overnight under the
clouds...thus the travel hazard threat from any freezing rain
appears very insignificant.


Short term...(this evening through sunday)
issued at 253 PM CST Sat Nov 28 2015

Tonight and Sunday...

While the north will see surface
high pressure continuing to spread in...the flow aloft will remain
from the southwest. This will bring more middle clouds northeast over
nearly all of the County Warning Area...and creates a situation where models are
likely underestimating cloud cover. As is the case right now...there
are clear skies to the north...but all areas in the southwest flow
from Interstate 80 southward...are 100% cloudy. Model output has
been too low on sky %s...and will try to play the forecast as binary
as I can in the short going cloudy where I believe the
edge will be...and clear in the north. Then...later tonight and
tomorrow...going fully cloudy in the middle cloud regime as the over
running continues aloft. Under the cloud covered areas in the south
half...radiational cooling will not be a large factor...and the
light surface winds should not be a significant cold air advection input. Thus...I
have gone milder than guidance in the south by a few degrees...and
near guidance in the north. Models continue to show a few weak
rounds of forcing for showers similar to this afternoon in the far
south later tonight and early Sunday. Measurable rain will again be
somewhat of a challenge...but some sprinkles will likely reach the
ground. I will keep low probability of precipitation going...and continue mention of
freezing rain after midnight in the southwest. With clouds over that
area all night...and surfaces not much below seems
that the threat for freezing rain hazards is very very low. Amounts
of rain if they do measure...should be generally 0.05 or less.

Long term...(sunday night through saturday)
issued at 253 PM CST Sat Nov 28 2015

Sunday night through next Saturday...

Forecast focus on storm system early next week otherwise a dry
period with near seasonal temperatures.

Sunday night through Tuesday night...storm system currently in The
Rockies expected to track across central Iowa Monday night and then
into northern WI on Tuesday. Deterministic models similar and
confidence is high that the significant snowfall associated with
this system will remain west and north of the dvn County Warning Area. There is a
brief window for light freezing rain in our northwest counties early
Monday at the onset of the precipitation.

For much of Monday through Monday evening this will be a rain event
with rainfall amounts of around one-half inch or less. Pwat's rise
to near an inch on Monday. After midnight Monday night and through
Tuesday the system lifts to our north with a dry slot cutting off
the deeper moisture. In the meantime...the colder air arrives to
turn what moisture is left to light snow or flurries but
accumulations look to be about an inch or less in the deformation
zone on the back side of the system...mainly north of Interstate 80.
There is a slight chance of some very light snow or flurries that
may linger into Tuesday night. Maximum temperatures will range from
the upper 30s to lower 40s at most locations Monday and Tuesday.

Wednesday through next Saturday...northwest flow aloft on Wednesday
behind the departing storm system becomes southwest by Saturday
ahead of an approaching long wave trough. For much of this period a
sprawling surface high will be located across the eastern and
southern United States. This will cut-off any Gulf moisture
transport northward for the time being so this should be a dry
period. Temperatures will be near normal to slightly above normal
with highs mainly in the upper 30s to middle 40s...and lows mainly in
the 20s.



Aviation...(for the 00z tafs through 00z Sunday evening)
issued at 538 PM CST Sat Nov 28 2015

VFR conditions to continue for the next 24 plus hours despite considerable
middle/hi clouds streaming over the region with the thickest and lowest
in the south. The brl terminal may see ceilings as low as 5k above ground level at times
with very light rain or sprinkles possible to the south but coverage
not enough to put a vicinity description in. Winds will be light northerly
shifting mainly to the northeast by Sunday.


Dvn watches/warnings/advisories...



short term...Ervin
long term...haase

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