Area Forecast Discussion
Issued by NWS Des Moines, IA

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500
FXUS63 KDMX 261043
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
543 AM CDT Sat May 26 2018

.SHORT TERM.../Today through Tonight/
Issued at 324 AM CDT Sat May 26 2018

A few storms remain across the state early this morning with all of
the activity now out of the area and into the southeast portion of
the state. An isolated cell may still bubble up across the far
southeast through the next hour or two as the cluster to the east
continues to move east southeast. Otherwise dry conditions are
expected throughout today into tonight across the forecast area as
an area of high pressure builds into the state. A few storms may
still develop along the far east/southeastern edge of the high, with
the majority of the activity expected to remain east/south of the
area into northern MO. Therefore have removed the small mention of
pops in the far southeast for late this afternoon, however did leave
pops in the 10-14 range for a few hours with the activity expected
to be nearby and still can`t completely rule out an extremely
isolated storm in the far southeast. Slight WAA expected across the
area today with h85 temps into the low 20s Celsius. Areas just to
the west with this airmass pushed into the low to mid 90s, therefore
continued the forecast of low to mid 90s for all of the forecast
area as well. This will push high temps to near record values, with
many record highs currently in the mid 90s for this date across the
area.

High pressure to remain across the area tonight with clear skies
expected with the upper ridge building into the region aloft.
Continued push of warmer air and winds shifting around to the south
should allow for mild temperatures tonight with lows into the mid to
upper 60s and a few temps around 70 overnight.

.LONG TERM.../Sunday through Friday/
Issued at 324 AM CDT Sat May 26 2018

The hot weather will persist through the remainder of the weekend
into Memorial Day with the upper level ridge over the region and
850mb temperatures around 20C. The 25/00z GEFS Extreme Forecast
Index has much of central Iowa in the 90th if not the 95th
percentile for temperature at 00z on Sunday and Monday. So
certainly temperatures are on the far end of the reference
climatology and not surprising that tying or breaking records
highs remains possible on both days. While the temperatures will
be extreme for late May, heat index values will be kept in the 90s
as dewpoints mix out in the afternoon down into the low to middle
60s on both days. While it will be a prolonged stretch of warm
weather, still not planning on any headlines. 850mb temperatures
will begin a slow downward trend Tuesday into Wednesday as a
western US trough begins to lift northeastward from the
Intermountain West. The GFS maintains this as more neutral to
perhaps negatively tilted while the ECMWF is more positively
tilted. Chances for showers and thunderstorms will slowly increase
on Tuesday as Q-vector convergence gradually moves into the state
with the best chances Tuesday night into Wednesday. Storm may
linger on Wednesday, but this is somewhat unclear as the
convergence weakens later in the day due to the proximity of
subsidence from the remnants of Alberto. Otherwise as this trough
exits the area, there is little in the way of cooler air behind
it and heights will be rising by the end of the week with
temperatures remaining well above normal.

&&

.AVIATION.../For the 12Z TAFS through 12Z Sunday morning/
Issued at 543 AM CDT Sat May 26 2018

VFR conditions expected throughout the TAF forecast period. Winds
to remain light and somewhat variable through the period. During
the afternoon hours will be more predominantly out of the west to
northwest and late tonight shifting around to the south. All
remaining around 6 kts of less.

&&

.CLIMATE...
Issued at 324 AM CDT Sat May 26 2018

.Forecast/Record Highs for Official Central Iowa Climate Sites...

====================================================================
            |       Saturday       |        Sunday        |  Period
            |  Forecast   Record/  |  Forecast   Record/  |    of
City        |    High      Year    |    High      Year    |  Record
====================================================================
Des Moines        94     93/1985         96      91/2012      1878-
Waterloo          93     94/1967         96      93/1900      1895-
====================================================================

====================================
            |        Monday        |
            |  Forecast   Record/  |
City        |    High      Year    |
====================================
Des Moines        92     92/1895
Waterloo          95     93/2006
====================================

&&

.DMX WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...Beerends
LONG TERM...Ansorge
AVIATION...Beerends
CLIMATE...Ansorge



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