Flash Flooding and Hail in Kansas, May 4, 2015

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
1231 PM CDT Mon May 4 2015

...Update to aviation forecast discussion...

.SHORT TERM...(Today and Tonight)
Issued at 332 AM CDT MON MAY 4 2015

Early this morning a frontal boundary extended from southwest Iowa
into west central Kansas. A surface low was located over north
central Kansas along the frontal boundary. Low level jet has been
oriented parallel to the frontal zone. Outflow boundary from eastern
Nebraska convection was moving southwest across northeast Kansas at
08Z. Could see some elevated activity along this boundary early this
morning until the low level jet weakens. Water vapor loop shows a
shortwave across northeast New Mexico. This shortwave is forecast to
move northeast along the frontal zone today reaching southeast
Nebraska by early evening. Showers ahead of the wave in southwest
Kansas may move into central and north central Kansas this morning.
The frontal boundary will sag south and extend from north central
Missouri to near Salina to southwest Kansas. Models continue to show
marginal shear around 20 to 30 kts south of the front and 30 to
40 kts near and north of the front. MUCAPE varies from 1000-2000
J/kg this afternoon and may likely be lower in parts of north
central Kansas where more clouds are expected with the above
mentioned wave and morning precipitation. Main hazards will be large
hail and strong winds. A tornado is also possible across north
central and central Kansas near the surface low in central Kansas
this afternoon. Forecast soundings show good low level turning in
the hodograph with helicity around 300 m2/s2. Tonight the low level
jet will become oriented perpendicular to the the frontal boundary
with elevated thunderstorms possible north of I-70. The convection
should sift to the north through the night as the nearly stationary
front lifts north as a warm front into southern Nebraska. Will keep
highest probability near the Nebraska border with areas south of
I-70 likely remaining dry overnight. Locally heavy rainfall will be
possible across north central and northeast Kansas tonight.
Temperatures will continue to be warm with highs in the upper 70s to
lower 80s and lows in the upper 50s to lower 60s.

.LONG TERM...(Tuesday through Sunday)
Issued at 332 AM CDT MON MAY 4 2015

Models continue to show an active, wet pattern being in place across
the region through the end of the week and even through the weekend.
By Tuesday morning, models show Monday's cold front progressing
northward into southern Nebraska as a warm front due to the
mid-level ridge centered over the southeastern U.S. building
northward into the Central Plains. This boundary should remain north
of the area, resulting in the best chance this week for dry
conditions across the majority of the forecast area. Have kept
slight chance PoPs in for far north central Kansas as the boundary
may be close enough for associated precipitation to skim the area.
However, these dry conditions will be short-lived as a mid-level
trough over the southwestern U.S. is progged to lift northeastward
into the Central Plains Tuesday night into Wednesday, supplying
decent forcing to support thunderstorm development across the region
so have likely to definite PoPs across the entire forecast area.
While models show this trough continuing to lift northward into the
Northern Plains Wednesday night into Thursday, another mid-level
closed low looks to develop along the west coast and follow a
similar track into the southwestern U.S. before lifting
northeastward into the Rockies and High Plains by the weekend. With
this mid-level pattern in place, surface low pressure should remain
anchored over the High Plains and central U.S., resulting in
continued mild temperatures and persistent southerly flow advecting
moisture from the Gulf of Mexico. This steady stream of moisture
from the Gulf northward into the region, combined with forcing from
the stalled out cold front just west of the area and a few weak
embedded shortwaves, will help to support the potential for
scattered shower and thunderstorm chances through the end of the
week and into the weekend. However, the exact timing and location of
this cold front along with any weak embedded waves is still
uncertain amongst the models, so confidence is low in when the best
periods for precipitation will be from late week through the
weekend. Models suggest that the cold front may advance a bit
further east by Friday, stretching into portions of far northern
Kansas which would help to promote better chances for precipitation.
However, models also show this boundary stalling out over the region
into the weekend with the next approaching mid-level trough finally
helping to push the cold front eastward across the area on Sunday.

Expect temperatures to remain fairly consistent across the region
this week and through the weekend as the surface pattern remains
fairly unchanged.  The persistent southerly flow will support the
steady advection of warm, moist air into the region with highs in
the 70s, lows in the upper 50s/low 60s, and dewpoints in the 50s and
60s.

&&

.AVIATION...(For the 18Z TAFs through 18Z Tuesday Afternoon)
Issued at 1231 PM CDT MON MAY 4 2015

Only minor changes to going forecast. Shifted VCTS concern one hour
later but confidence in any time or location seeing TS is too low
for inclusion. South winds increase late in the period.

&&

.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

SHORT TERM...53
LONG TERM...Hennecke
AVIATION...65

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TOPEKA KS
539 AM CDT MON MAY 4 2015

KSZ008>012-020>024-026-034>040-054>056-058-059-051045-
REPUBLIC-WASHINGTON-MARSHALL-NEMAHA-BROWN-CLOUD-CLAY-RILEY-
POTTAWATOMIE-JACKSON-JEFFERSON-OTTAWA-DICKINSON-GEARY-MORRIS-
WABAUNSEE-SHAWNEE-DOUGLAS-LYON-OSAGE-FRANKLIN-COFFEY-ANDERSON-
539 AM CDT MON MAY 4 2015

THIS HAZARDOUS WEATHER OUTLOOK IS FOR EAST CENTRAL...NORTH
CENTRAL AND NORTHEAST KANSAS.

.DAY ONE...TODAY AND TONIGHT.

THERE IS A CHANCE OF THUNDERSTORMS TODAY AND TONIGHT ACROSS MUCH
OF THE OUTLOOK AREA WITH THE HIGHER PROBABILITY NORTH OF
INTERSTATE 70. SOME OF THE STORMS MAY BE SEVERE THIS AFTERNOON
AND TONIGHT WITH LARGE HAIL AND DAMAGING WINDS THE MAIN HAZARDS.
A TORNADO IS ALSO POSSIBLE MAINLY WEST OF A HERINGTON TO JUNCTION
CITY TO WASHINGTON LINE THIS AFTERNOON AND EVENING. LOCALLY HEAVY
RAINFALL IS ALSO EXPECTED NORTH OF INTERSTATE 70.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

THUNDERSTORMS ARE LIKELY ACROSS THE OUTLOOK AREA WEDNESDAY AND
WEDNESDAY NIGHT. A FEW OF THESE STORMS COULD POTENTIALLY BE
STRONG TO SEVERE...PRIMARILY ACROSS NORTH CENTRAL KANSAS.

STRONG TO SEVERE THUNDERSTORMS ARE POSSIBLE SATURDAY AND SATURDAY
NIGHT ACROSS THE OUTLOOK AREA.

.SPOTTER INFORMATION STATEMENT...

SPOTTERS MAY BE NEEDED THIS AFTERNOON OR EVENING.

&&

MORE DETAILED INFORMATION CAN BE ACCESSED AT...
HTTP://WWW.WEATHER.GOV/TOP/SITREP

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE TOPEKA KS
256 PM CDT MON MAY 4 2015

KSZ023-042030-
POTTAWATOMIE-
256 PM CDT MON MAY 4 2015

...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN POTTAWATOMIE
COUNTY...

THROUGH 330 PM CDT...A STRONG THUNDERSTORM WILL MOVE NORTHEAST AT 30
MPH ACROSS PORTIONS OF NORTHEASTERN POTTAWATOMIE COUNTY. NATIONAL
WEATHER SERVICE DOPPLER RADAR INDICATED THIS STORM IS CAPABLE OF
PRODUCING NICKEL SIZE HAIL. SOME LOCATIONS THAT COULD BE AFFECTED
INCLUDE ONAGA AND HAVENSVILLE.

STAY ALERT TO THE WEATHER IN CASE A WARNING IS ISSUED.

&&

LAT...LON 3946 9603 3945 9604 3940 9639 3952 9645
      3957 9619 3957 9611
TIME...MOT...LOC 1956Z 243DEG 26KT 3949 9631