Red Flag Warning 1, NWS Sioux Falls, SD

096 
WWUS83 KFSD 300011
RFWFSD

URGENT - FIRE WEATHER MESSAGE
National Weather Service Sioux Falls SD
711 PM CDT Sun Apr 29 2018


IAZ002-003-012>014-020>022-031-032-MNZ081-090-300115-
/O.EXP.KFSD.FW.W.0001.000000T0000Z-180430T0000Z/
Osceola-Dickinson-Sioux-O'Brien-Clay IA-Plymouth-Cherokee-
Buena Vista-Woodbury-Ida-Cottonwood-Jackson-
711 PM CDT Sun Apr 29 2018

...RED FLAG WARNING HAS EXPIRED FOR STRONG WINDS AND LOW HUMIDITY
FOR FIRE WEATHER ZONES 002, 003, 012, 013, 014, 020, 021, 022, 
031, 032, 081, AND 090...

Humidity values will continue to rise this evening, as well as
wind speeds slowly decreasing. That said, wind speeds will be
quite breezy all night, averaging 20 to 30 mph with higher gusts.

$$

MNZ071-072-080-089-097-098-300115-
/O.EXP.KFSD.FW.A.0001.000000T0000Z-180430T0000Z/
Lincoln MN-Lyon MN-Murray-Nobles-Pipestone-Rock-
711 PM CDT Sun Apr 29 2018

...FIRE WEATHER WATCH HAS EXPIRED FOR STRONG WINDS AND LOW
HUMIDITY FOR FIRE WEATHER ZONES 071, 072, 080, 089, 097, AND 
098...

Humidity values will continue to rise this evening, as well as
wind speeds slowly decreasing. That said, wind speeds will be
quite breezy all night, averaging 20 to 30 mph with higher gusts.

$$

Area Forecast Discussion
National Weather Service Sioux Falls SD
1251 PM CDT Sun Apr 29 2018

.SHORT TERM...(Today and Tonight)
Issued at 402 AM CDT Sun Apr 29 2018

Warm and windy today across the area as south winds increase through
the morning. Winds just above the surface are very strong and will
start to mix down a little after sunrise. By late morning into the
afternoon wind gusts around 45 mph will be likely in most locations.
The last to see the stronger winds will be northwest IA as high
pressure continues to drift east. Highs will be in the upper 60s to
mid 70s with some warmer readings in central SD. A wind advisory
will be in effect for most of the area. A fire weather watch is also
in effect for southwest MN where humidities may be the lowest the
longest. However, with winds as strong as they are in southeast SD
and northeast Nebraska critical fire weather may occur there as well.

This strong pressure gradient will be in place through the night as
a trough of low pressure aloft works into the eastern Rockies.
Temperatures will be very mild with lows in the mid and upper 50s.
Mid level forcing and instability may result in a few showers and
thunderstorms tonight, with the better chances across northwest IA
and southwest MN. At this time elevated instability does not look
strong enough to support any severe weather but lightning will be a
possibility with CAPE values of 300 to 500 J/kg.

.LONG TERM...(Monday through Saturday)
Issued at 402 AM CDT Sun Apr 29 2018

Monday will see a continuation of strong winds, especially along
and east of Interstate 29. A little enhanced heating/mixing is
expected as a cool front moves into eastern SD in the afternoon
and highs may reach the 80s in many locations for the first time
since last September. As the front moves into eastern SD in the
afternoon a few thunderstorms may be possible but for now will not
plan on anything before about 7 pm as surface based convection
looks capped and mid levels are dry. However, by evening and
overnight Monday into Tuesday morning an upper level wave will
approach from the southwest and will likely aid in producing
elevated convection. Some of these storms could become severe with
CAPE values likely around 1500 J/kg and decent layer bulk shear
values around 40 knots.

Tuesday still a bit up in the air regarding temperatures as
convection and upper level wave will likely drive cooler air into
the area during the morning. This should keep high temperatures in
the 60s. Will likely see some lingering showers and thunderstorms as
well. Will have to keep an eye on southern parts of northwest IA in
the afternoon and evening as another jet max approaches and winds
south of the boundary converge into the area. A few of these storms
would likely become severe as well if they develop.

The chance for showers and thunderstorms will continue into
Wednesday and Wednesday night as the jet energy and occasional mid
level waves enhance convergence on the low and mid level boundary.

Otherwise, highs generally in the 60s through Saturday.

&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1250 PM CDT Sun Apr 29 2018

Very strong winds surface and aloft will continue to produce the
most significant aviation concerns through 18z Mon. Surface wind
gusts of 30 to 40 knots will be common through the daytime hours,
before partial decoupling allows for development of very strong
LLWS tonight. Within 2kft AGL, south to south southwest winds from
50 to 60 kts are likely. This condition will again diminish by
early to mid morning as both mixing starts to balance out the
wind profile, and with the diurnal decrease in low-level jet.
As a result of the mixing, surface winds will again gust from 25
to 35 kts during the morning.

Elevated convection will be most likely tonight east of KFSD/KSUX.
At this point, confidence in location and timing will keep from
mentioning in the TAF at either site, as well as likelihood that
conditions will remain VFR even within such showers/thunderstorms.

Finally, there could be development of some lower clouds below the
inversion. However, with moisture somewhat lacking, more likely to
be either a very brief period for ceiling potential or none at
all. Have put in some scattered clouds by tomorrow morning at
2.5-4kft AGL to hint at potential.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...Wind Advisory until 8 PM CDT this evening for SDZ038>040-050-
     052>071.

MN...Wind Advisory until 8 PM CDT this evening for MNZ071-072-080-089-
     097-098.

     Fire Weather Watch until 7 PM CDT this evening for MNZ071-072-
     080-081-089-090-097-098.

IA...Wind Advisory until 8 PM CDT this evening for IAZ001-002-012-013-
     020-031.

NE...Wind Advisory until 8 PM CDT this evening for NEZ013-014.

&&

SHORT TERM...08
LONG TERM...08
AVIATION...Chapman

Hazardous Weather Outlook
National Weather Service Sioux Falls SD
437 AM CDT Sun Apr 29 2018

IAZ001>003-012>014-020>022-031-032-MNZ071-072-080-081-089-090-097-
098-NEZ013-014-SDZ038>040-050-052>071-300945-
Lyon IA-Osceola-Dickinson-Sioux-O'Brien-Clay IA-Plymouth-Cherokee-
Buena Vista-Woodbury-Ida-Lincoln MN-Lyon MN-Murray-Cottonwood-
Nobles-Jackson-Pipestone-Rock-Dixon-Dakota-Beadle-Kingsbury-
Brookings-Gregory-Jerauld-Sanborn-Miner-Lake-Moody-Brule-Aurora-
Davison-Hanson-McCook-Minnehaha-Charles Mix-Douglas-Hutchinson-
Turner-Lincoln SD-Bon Homme-Yankton-Clay SD-Union-
437 AM CDT Sun Apr 29 2018

This Hazardous Weather Outlook is for portions of northwest Iowa,
west central Iowa, southwest Minnesota, northeast Nebraska,
central South Dakota, east central South Dakota, south central
South Dakota, and southeast South Dakota.

.DAY ONE...Today and Tonight

South winds will increase through the morning and become strongest
in the afternoon, with gusts around 45 mph likely. Along with the
strong winds will be somewhat dry air which may create critical
fire weather conditions across the area.

Minor to moderate flooding will continue along many rivers and
streams, including the James, Big Sioux, Split Rock, Des Moines
and Little Sioux.

.DAYS TWO THROUGH SEVEN...Monday through Saturday

Scattered showers and thunderstorms will be possible Sunday night
through Monday night. Storms in Central South Dakota Monday night
may produce large hail and damaging winds. Parts of northwest Iowa
could see strong to severe storms Tuesday night as well.

Minor to moderate flooding is forecast to continue through mid to
late week on many rivers and streams due to the recent snowmelt.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed.