Severe Thunderstorm Warning 270, NWS Des Moines, IA

133 
WWUS53 KDMX 261842
SVSDMX

Severe Weather Statement
National Weather Service Des Moines IA
142 PM CDT SAT AUG 26 2017

IAC151-261852-
/O.EXP.KDMX.SV.W.0270.000000T0000Z-170826T1845Z/
Pocahontas IA-
142 PM CDT SAT AUG 26 2017

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN POCAHONTAS COUNTY
WILL EXPIRE AT 145 PM CDT...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore the warning will be allowed to expire.  However small hail
is still possible with this thunderstorm.

LAT...LON 4282 9467 4281 9444 4279 9444 4256 9445
      4263 9477
TIME...MOT...LOC 1842Z 282DEG 17KT 4269 9443 

$$

Beerends

Area Forecast Discussion
National Weather Service Des Moines IA
1249 PM CDT Sat Aug 26 2017

...Updated Aviation Discussion...

.SHORT TERM.../Today through Tonight/
Issued at 313 AM CDT Sat Aug 26 2017

Similar to previous overnights...area of showers and
thunderstorms is evolving over northwest Iowa and eastern
Nebraska...slowly weakening as it moves to the east with the
stronger portion of the line sagging south toward southeast
Nebraska now. Weak low pressure trough still expected to move east
across the area by tonight. Current storms should continue to
diminish through the morning hours with lingering showers/isolated
thunder mainly west and north with showers east of the weakening
area. Some uncertainty as to whether much will happen until late
afternoon after the morning showers and weakening convection
further dissipates. Little overall synoptic forcing and surface
convergence will inhibit any organization or trigger until
instability increases again by late afternoon/early evening.
Currently SPC outlook for the south/southwest for slight risk this
afternoon/evening. Though instability of 2000 to 2500 j/kg does
support stronger storms...wind shear lacking to any great extent
and little in terms of overall sfc convergence so coverage of any
strong storms likely to be very limited. Wind/hail would be the
main concerns. As the trough/cool front moves southeast tonight
expect that the scattered areas of thunderstorms will continue but
weaken overnight toward morning. Highs today will again reach the
70s to lower 80s with lows tonight a bit warmer south in the mid
60s due in part to cloud cover and storm potential as well as
southwest winds south of the boundary. Northern areas will brush
with 60 with cooler air beginning to filter in from the northwest.

.LONG TERM.../Sunday through Friday/
Issued at 313 AM CDT Sat Aug 26 2017

An upper level ridge will prevail over the western US through the
remainder of the weekend into early next week. During this time, an
upper area of low pressure will drop out of central Canada moving
over eastern Iowa into the Ohio Valley. This upper low will
essentially cut off what could have been an exit for present
Hurricane Harvey, which will remain over the southeastern part of
Texas through the week as steering currents remain weak. While
we're far removed from the impacts of Harvey tonight, our thoughts
are with those impacted by Hurricane Harvey, including our NWS
colleagues.

Back closer to central Iowa, the aforementioned upper low drops
into Minnesota on Sunday with a surface cold front sweeping
through most of the forecast area by the afternoon. This will
confine the best shower and stronger thunderstorm chances to
eastern and far southern Iowa where better instability and lift
will be located. Behind the cold front, isolated showers and
thunderstorms will be possible as the cooler temperatures aloft
begin to arrive, making it favorable for air parcels to rise with
steep low level and modest mid-level lapse rates.

As the new work week begins, the upper low will arrive over eastern
Iowa with diurnal showers and perhaps isolated thunderstorms Monday
afternoon into early evening. The most favored areas for any
rainfall will be east of a Waterloo to Ottumwa line, or roughly east
of Highway 63, which is closer to the upper low. Overall, forecast
soundings for KALO and KOTM show rather meager values of CAPE so
thunder should be isolated. With breezy northerly winds on Monday,
did adjust highs down a degree or so from Superblend over northern
Iowa. Overall, Monday's highs will be below normal by a few to
several degrees. As surface high pressure builds in Monday night
into Tuesday morning, clear skies and light north winds should
allow decent cooling so have lowered temperatures a few degrees
outside of urban areas.

Tuesday through the end of the week will feature highs mainly in the
upper 70s to lower 80s (near normal) with lows in the upper 50s
to lower 60s as low return to normal in the latter part of the
week. Rain chances will remain low through the middle part of the
week as the high moves across the region. Any rain chances will be
relegated to northeast Iowa later Thursday and again later Friday
as a weak shortwave comes across the western US ridge.

&&

.AVIATION.../For the 18Z TAFS through 18Z Sunday afternoon/
Issued at 1242 PM CDT Sat Aug 26 2017

A weak cluster of showers/storms may impact ALO/MCW/FOD this
afternoon. Otherwise, cold front to bring MVFR stratus late
tonight into Sunday morning for all TAF sites. Potential for this
stratus to linger through much of the morning hours Sunday.

&&

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

&&

SHORT TERM...REV
LONG TERM...Ansorge
AVIATION...Podrazik

Hazardous Weather Outlook
National Weather Service Des Moines IA
1017 AM CDT Sat Aug 26 2017

IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-
081>086-092>097-271530-
Emmet-Kossuth-Winnebago-Worth-Palo Alto-Hancock-Cerro Gordo-
Pocahontas-Humboldt-Wright-Franklin-Butler-Bremer-Sac-Calhoun-
Webster-Hamilton-Hardin-Grundy-Black Hawk-Crawford-Carroll-Greene-
Boone-Story-Marshall-Tama-Audubon-Guthrie-Dallas-Polk-Jasper-
Poweshiek-Cass-Adair-Madison-Warren-Marion-Mahaska-Adams-Union-
Clarke-Lucas-Monroe-Wapello-Taylor-Ringgold-Decatur-Wayne-
Appanoose-Davis-
1017 AM CDT Sat Aug 26 2017

This Hazardous Weather Outlook is for portions of central Iowa.

.DAY ONE...Today and tonight

Isolated thunderstorms are expected throughout the day today into
the evening. The severe weather threat is low, but a brief
stronger storm is possible with hail and gusty wind threat.

.DAYS TWO THROUGH SEVEN...Sunday through Friday

Isolated thunderstorms are possible Sunday with the better
chances over eastern and far southern Iowa. The risk of severe
storms is low.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated.

KLP

Special Weather Statement
National Weather Service Des Moines IA
1028 AM CDT SAT AUG 26 2017

IAZ015-023-261615-
Palo Alto IA-Pocahontas IA-
1028 AM CDT SAT AUG 26 2017

...SPECIAL WEATHER STATEMENT...

At 1028 AM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from 6 miles northeast of Lost Island Lake to near
Emmetsburg to near Albert City. Movement was east at 30 mph.

Half inch hail and winds in excess of 30 mph will be possible with
these storms.

Locations impacted include...
Emmetsburg, Pocahontas, Laurens, Five Island Lake, Silver Lake, Rush
Lake, Lost Island Lake, Graettinger, West Bend, Ruthven, Rolfe,
Mallard, Ayrshire, Havelock, Cylinder, Plover, Curlew, Rodman,
Kearney State Park and Pocahontas Municipal Airport.

LAT...LON 4325 9445 4274 9444 4267 9491 4325 9492
TIME...MOT...LOC 1528Z 263DEG 26KT 4325 9485 4314 9477 4270 9492

Beerends

Special Weather Statement
National Weather Service Des Moines IA
1138 AM CDT SAT AUG 26 2017

IAZ015-023-261715-
Palo Alto IA-Pocahontas IA-
1138 AM CDT SAT AUG 26 2017

...NICKEL HAIL AND 40 MPH WINDS POSSIBLE...

At 1137 AM CDT, Doppler radar was tracking a strong thunderstorm over
Silver Lake, or 11 miles southwest of Emmetsburg, moving east at 30
mph.

Nickel size hail and winds in excess of 40 mph will be possible with
this storm.

Locations impacted include...
Emmetsburg, Silver Lake, Rush Lake, Five Island Lake, Mallard,
Ayrshire, Curlew and Emmetsburg Municipal Airport.

LAT...LON 4313 9464 4287 9466 4288 9491 4312 9491
TIME...MOT...LOC 1637Z 267DEG 25KT 4304 9489

Beerends

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
1145 AM CDT SAT AUG 26 2017

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1130 AM     HEAVY RAIN       EMMETSBURG              43.11N 94.68W
08/26/2017  M1.35 INCH       PALO ALTO          IA   CO-OP OBSERVER

            THE HEAVY RAIN FELL BETWEEN 1100 AND 1130 AM
            CDT.

&&

BF

Special Weather Statement
National Weather Service Des Moines IA
1231 PM CDT SAT AUG 26 2017

IAZ023-024-035-261800-
Humboldt IA-Webster IA-Pocahontas IA-
1231 PM CDT SAT AUG 26 2017

...GUSTY WINDS POSSIBLE...

At 1230 PM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from 10 miles east of Laurens to 10 miles northwest
of North Twin Lake. Movement was east at 50 mph.

Half inch hail and winds in excess of 40 mph will be possible with
these storms.

Locations impacted include...
Pocahontas, Fonda, Rolfe, Gilmore City, Bode, Palmer, Clare,
Havelock, Rutland, Bradgate, Plover, St. Joseph, Ottosen, Pioneer and
Pocahontas Municipal Airport.

LAT...LON 4291 9476 4291 9419 4254 9435 4254 9444
      4256 9444 4256 9492
TIME...MOT...LOC 1730Z 273DEG 41KT 4290 9464 4259 9477

Beerends