Area Forecast Discussion
Issued by NWS Quad Cities, IA IL
FXUS63 KDVN 251148 AAA
Area Forecast Discussion...UPDATED
National Weather Service Quad Cities IA IL
648 AM CDT Sat Mar 25 2017
...12z AVIATION UPDATE...
Issued at 330 AM CDT Sat Mar 25 2017
Early this morning, a slow moving upper level low was located over
the central United States. At the surface, a double barrel surface
low appeared to be forming over MO and OK. A warm front that moved
through the CWA late Thursday had pushed south into the area as a
cold front off of the Great Lakes. This cold front and surface low
will drive the weather in the short term period.
.SHORT TERM...(Today and Tonight)
ISSUED AT 330 AM CDT Sat Mar 25 2017
Main question in the short term period is how much rain will fall.
Guidance has been overdone in the total QPF so far across the
area. Went with superblend for QPF. With the low being cutoff
guidance usually has a hard time with correct solutions, this
leads to low confidence in the model QPF. However, there is little
question that the the best chances for precip are tied to the sfc
boundary across the area. This boundary will move north through
the day, along with it the best chances for precip. Overall
confidence in the forecast is low.
As mentioned previously, there is definitely a chance for low top
convection today underneath the H5 low. If breaks in the sky can
occur, there will be a better chance for convection. There is
chance for low level storm rotation, especially if some of the
convection can move with the sfc boundary as it moves north. Brief
tornadoes cannot be ruled out along the surface boundary. As the
storms move quickly into the cold side of the boundary, rotation
may increase, however the chance for tornadoes will decrease
.LONG TERM...(Sunday through Friday)
ISSUED AT 330 AM CDT Sat Mar 25 2017
Sunday`s weather will be rather gloomy as the vertically stacked
upper low and surface low remain over the CWA through afternoon,
before moving off to the northeast as it continues to weaken. During
this process, areas of light rain showers will continue to be
possible. Rainfall should be rather light, but some isolated showers
will move rather slow, so isolated amounts over 0.25 are possible.
Temperatures and dewpoints will be closely tied to each other so it
will be springlike with light winds.
The low will move off Sunday night, only to be followed by another
push of moisture from the next low approaching the Mississippi
Valley. For now, it remains possible that this will bring rain to
the south half of the CWA Monday and Monday evening, but amounts
look very light and this could be a cloudy period if the storm drops
any farther south.
Tuesday and Tuesday night are confidently dry and at least some
decrease in clouds. By Wednesday, models are differing on the
arrival time of the next system. The model blend brought in pops to
the southwestern counties as warm advection begins, but this is a
very low confidence forecast. The ECMWF remains the most bullish on
the northerly track and stronger strength of the later week storm
system, while the operational GFS is farther south with the system
and has our region mainly impacted by dry northwest flow. For now,
the extended is biased towards the more stable ECMWF run.
.AVIATION...(For the 12Z TAFS through 12Z Sunday Morning)
ISSUED AT 619 AM CDT Sat Mar 25 2017
Difficult aviation forecast as CIGs and VSBYs will be bouncing
around as rain and possibly thunderstorms approach the area. Many
sites have had VSBYs improve tonight while CIGs remain low. Think
that any improvements from overnight will again return to IFR this
morning and during the day as the upper low moves in. Rain will be
possible off and on through the next 12 hours as well. Later
tonight, models suggests that LIFR cigs will be possible. Did not
add theses yet as confidence is low in it occurring.