Area Forecast Discussion
Issued by NWS Des Moines, IA

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FXUS63 KDMX 282327
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
527 PM CST Wed Feb 28 2024

 ...Updated for the 00z Aviation Discussion...

.KEY MESSAGES...

- Extreme fire weather conditions for portions of northwest Iowa
  Thursday. Red Flag Warning in effect.

- Record breaking warmth returns over the weekend.

- Rain and thunderstorms possible late Sunday with some
  lingering wintry precip behind.

&&

.DISCUSSION...
Issued at 256 PM CST Wed Feb 28 2024

An area of high pressure is located to the southwest of the state
this afternoon. Northwest flow allows for colder air to reside this
afternoon where highs will only be in the 30s and upper 20s north.
The dry air, subsidence, and cold air advection have kept breezy
conditions in place this afternoon. Winds will subside this evening
as a ridge exits pivots overhead and diurnal heating is lost. The
thin layer of snow pack may disappear almost entirely today from
sublimation and warmth from direct sunlight. This will set up fuels
for the fire weather conditions tomorrow.

Elaborating on this, dry southwest flow will resume late tonight
into tomorrow. Lee side troughing will tighten the pressure gradient
against the slow departing high pressure and increase winds aloft.
Clear skies and a very dry airmass overall will allow for efficient
mixing in the morning. Clear skies and dry air will allow for
efficient momentum transfer of the H85 winds, leading to windy
conditions for much of the day. HREF ensembles probs paint the
northwest half of the state with definite (100%) wind gusts
exceeding 35mph. The southeast half of the state has weaker flow
which will reduce wind speeds. Nonetheless, the conditions
stated above create a scenario where temperatures and dew points
underperform. Have adjusted these parameters accordingly,
putting especially the northwest half of the area in Red Flag
Warning criteria. Have issued a Red Flag Warning to reflect
conditions, but this may be amended in upcoming forecast
packages if conditions reflect.

Warm air advection continues to boost temperatures into the weekend.
Have raised temperatures above NBM on Friday to reflect and similar
adjustments may be needed into the weekend. Near high temperatures
are in the forecast for Saturday, especially for locations such as
Des Moines, Mason City, and Waterloo. Record highs are forecasted
for much of the area on Sunday as temperatures reach the upper 70s
and near 80. Low level moisture advection picks up ahead of a
deepening wave on Sunday. A dry line will advance across the state
and bring a chance for rain and thunderstorms to the region. Any
severe potential remains questionable as Pacific moisture appears it
may lag behind the low level moisture advection. Enough moisture may
lag behind the system to bring frozen precipitation into the
forecast to start next week. Trends will continue to be
monitored.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 527 PM CST Wed Feb 28 2024

VFR conditions will persist through the period. Winds will shift
to out of the south through this evening. By Thursday morning
winds will increase and a short period of LLWS is expected
across KFOD/KMCW/KDSM. Eastern extent is less certain so have
kept from KALO/KOTM for now. By Thursday afternoon LLWS will
diminish and southwest winds across all sites will gust over 30
kts through the afternoon.

&&

.CLIMATE...
Issued at 256 PM CST Wed Feb 28 2024

.Record vs Forecasted Max Temps on 3/2 and 3/3 for Select
Central Iowa Cities...

=============================================
            |  Sat 3/2    Previous  | Period
            | Forecasted   Record/  |   of
City        |   Max T       Year    | Record
=============================================
Des Moines        69      75/1983      1878-
Mason City        64      64/1963      1903-
Ottumwa           69      74/1983      1923-
Waterloo          67      71/1923      1895-
=============================================

=============================================
            |  Sun 3/3    Previous  | Period
            | Forecasted   Record/  |   of
City        |   Max T       Year    | Record
=============================================
Des Moines        79      81/1983      1878-
Mason City        73      69/1983      1903-
Ottumwa           78      79/1983      1923-
Waterloo          77      70/1983      1895-
=============================================

&&

.DMX WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from 10 AM to 6 PM CST Thursday for
IAZ004>007-015>017-023>028-033>039-044>049-057>060-070>072-081-
082-092-093.

&&

$$

DISCUSSION...Jimenez
AVIATION...Hagenhoff
CLIMATE...Jimenez


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