Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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763
FXUS63 KDVN 261733
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
1233 PM CDT Thu Apr 26 2018

...18z AVIATION UPDATE...

.SYNOPSIS...
Issued at 231 AM CDT Thu Apr 26 2018

Ridging surface and aloft north of a closed low in Arkansas was
providing light to calm winds across our area. Early morning
temperatures ranged from the mid 30s to lower 40s.

&&

.SHORT TERM...(Today and Tonight)
ISSUED AT 231 AM CDT Thu Apr 26 2018

Today: Mostly sunny and warmer ahead of a weak cold front arriving
later this afternoon and into early this evening. Forecast
soundings indicate the airmass will be quite dry (especially the
low levels), and the convergence along the front looks weak. Most
of the models indicate a dry FROPA except the HRRR does suggest
isolated showers or sprinkles along the front. For now I will
continue the dry forecast and the day shift can monitor model
trends. Highs will be around 70 but if the mixing is deeper than
expected then temperatures may be a bit higher. Southwest winds
will shift to the west then northwest with the passage of the front.

Tonight: A band of mainly mid level clouds will accompany the
front with clearing skies expected later tonight. Lows should dip
in the mid 30s to lower 40s.

.LONG TERM...(Friday through Wednesday)
ISSUED AT 231 AM CDT Thu Apr 26 2018

A strong secondary cold front will sweep through the region in
northwest flow Friday. The timing of this system should actually
place our area in deeply mixed west to northwest winds Friday. That
deep mixing should bring a mainly dry day, with wind and warm
temperatures supporting some elevated fire risk with GFDI (Grassland
Fire Danger Index) supporting the high range during the afternoon
hours. Virga or sprinkles may develop in the northeastern counties
in the afternoon as the main wave passes by, but with such deep
mixing, the chance for measurable rainfall is rather low.

Friday night through Saturday night, the chilly Canadian high will
dominate with lows in the mid 30s to near 40 and highs in the mid
50s to near 60. Since sunshine is expected, this still represents a
decent spring day. That high pressure will be on the move, with
return flow arriving Sunday and Monday.  That will bring warm air to
the region, along with possibly gusty winds and more elevated fire
risks, which are not yet certain.

During the Monday through Tuesday time frame, the upper pattern will
see a persistent and energetic western trof, with a gradually open
gulf situation. That will increase the dewpoints and deep moisture,
especially Tuesday through Thursday, as moisture converges into the
somewhat stationary surface front near Iowa. Temperatures will be
mild day and night, with lows only falling the 50s to lower 60s
Monday night through Wednesday night.

Rainfall could be widespread and plentiful, a welcome rain for most
interests given how dry the past week has been during this sustained
warm up. At this point, I could see amounts from 1 to 2 inches
being common in much of the area Tuesday through Thursday.
However, the position of the front and convective trends (we are
expecting thunderstorms) will determine who gets the higher
amounts and we just don`t know that yet.

&&

.AVIATION...(For the 18Z TAFS through 18Z Friday Afternoon)
ISSUED AT 1220 PM CDT Thu Apr 26 2018

VFR conditions will prevail through this TAF cycle. Southwest
winds around 5-15 kts will shift to the northwest this evening as
a weak cold front moves across the region. By late Friday morning,
winds will shift to the west and increase ahead of a strong cold
front.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&

$$

SYNOPSIS...Haase
SHORT TERM...Haase
LONG TERM...Ervin
AVIATION...Speck



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