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Area forecast discussion
National Weather Service Quad Cities Iowa Illinois
514 PM CST Mon Nov 20 2017

..aviation update...

issued at 305 PM CST Mon Nov 20 2017

Strong warm air advection in advance of a cold front over the northern and Central
Plains, combined with deep mixing aided by abundant sunshine and
gusty SW winds has pushed temps well above normal today and in the
mid 50s to lower 60s. These warmer temps and gusty winds combined
with lowering relative humidity and dry surface fuels also leading to a very high
fire danger this afternoon. The aforementioned cold front will
sweep across the area late tonight through early Tuesday morning,
and will bring a marked change to colder conditions on brisk northwest winds


Short term...(this evening through tuesday)
issued at 305 PM CST Mon Nov 20 2017

Cold front will sweep across the area in the pre-dawn to mid morning
hours on Tuesday. Much of tonight will be spent in the pre-frontal
warm sector characterized by continued gusty south-southwest winds, which along
with increasing high clouds will aid in more of a gradual descent on
temps tonight, until late northwest County Warning Area when cold front begins to make
inroads. As a result, lows will vary from coldest northwest (lower 30s) to
warmest southeast (around 40/lower 40s). On Tuesday, temps only expected to
rebound a few degrees from am lows before strengthening cold air advection on brisk northwest
winds likely results in falling temps through the 30s. Forecast
soundings supportive of gusts around 30 mph, but added momentum Transfer
due to strong cold air advection could aid in some areas being not far off from
Wind Advisory criteria (sustained 30 mph and/or gusts to 45 mph) per
tropopause pressure (down to 500-600 mb per nam) and potential vorticity.
Also, potential for some light precip streaking toward County Warning Area on Tue
from the plains attendant to band of mid level frontogenetical forcing.
This forcing is shown to weaken considerably while approaching. In
addition, soundings show top down saturation to around 7-9kft agl with
a large dry wedge beneath. Therefore, have left out any mention as
thinking mainly virga although can't rule out some sprinkles or maybe even
a flurry in some areas by mid morning exiting midday south/east of the
Quad Cities.

Long term...(tuesday night through monday)
issued at 305 PM CST Mon Nov 20 2017

Mainly dry weather, and variable temperature fluctuations still on
track through the long term. Travel conditions for Thanksgiving
still look good for a large part of the conus, with any potential
travel spots being in the Pacific northwest and portions of the far southeast.

After a cold midweek, it still looks like a decent albeit short term
warm-up is in store late week peaking on Friday. Nudged highs on Friday
up above blended guidance and more in range from mid 50s to lower 60s.
However, 925 mb temps on GFS and European model (ecmwf) are shown to be several degs
warmer (10-14c) than those of today (9c) with gusty SW winds, thus
potential to be much warmer than going forecast with more widespread
lower to middle 60s and possibly a few upper 60s. These temps would be
very close to record highs. Temps then look to return near to below
normal next weekend with the passage of another cold front, leading to
highs in the 30s to lower 40s.


Aviation...(for the 00z tafs through 00z Tuesday evening)
issued at 512 PM CST Mon Nov 20 2017

Southwest winds around 12 to 15 kts will continue overnight, as an
approaching cold front brings high clouds to the region. The cold
front will arrive in the mid morning hours Tuesday, as winds
switch to northwest and increase to 15 to 25 kts. At this time,
low clouds are not expected to form near or behind the front.


Dvn watches/warnings/advisories...


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