River Flood Warning 54, NWS Topeka, KS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TOPEKA KS
635 AM CDT Thu Jun 11 2015

...Update to aviation forecast discussion...

.SHORT TERM...(Today and Tonight)
Issued at 318 AM CDT THU JUN 11 2015

Early Thursday morning, a large MCS was tracking steadily east
across the forecast area, driven by a well-developed short wave
trough and 50 kt LLJ impinging upon an outflow boundary and
providing a continuous moisture influx across KS. According to
observations across the area, much of the stronger convection on the
leading edge of the system with more access to instability has
actually had weaker rainfall rates than expected with a bit of drier
air to overcome. However, the second and third rounds of enhanced
convection in some areas have had rates in the 1-1.5 inch per hour
range. So, while the leading edge of the MCS continues its eastward
progression, the attention is on the potential for continued
redevelopment on the western fringes of the MCS but still in advance
of the short wave energy aloft. In recent hours, have seen these
enhancements in central KS, including a particularly impressive
enhancement in conjunction with an MCV just west of Concordia at 330
AM. Will need to closely monitor flash flood potential with any
additional convection through the morning given the intense rainfall
rates as any persistent storms over an area could easily lead to
localized flash flooding. FWIW, dual pol precip estimates appear to
have been a bit high especially in north central KS while the legacy
estimates have been a bit low based on ground truth observations.
Expect this MCS to linger across northeast Kansas through around mid
morning before weakening and moving east of the area by noon as the
LLJ also weakens.

A primary question regarding late day thunderstorm forecast is just
how much the atmosphere will recover in the wake of morning
activity. Current expectation is that boundary layer moisture will
be ample in the wake of the system and temperatures will probably
recover well by mid afternoon, but the mid level lapse rates are
expected to be unimpressive. This should result in somewhere between
1000-2000 J/kg of MLCAPE in advance of an incoming cold front from
the north. Deep layer wind shear is likely to be in the 30-40 kt
range and sufficient for some storm organization although would like
to see steeper lapse rates before getting excited about severe
weather potential. Even still, potential for supercell structures
especially within the first few hours of development support some
hail potential. Tornado potential appears quite low (but not
impossible) and limited to the late afternoon and very early evening
hours. Locally damaging winds may be the greatest threat (although
still on the low end) through the afternoon and evening owing to the
presence of a 40 kt LLJ and potential for bowing segments near the
front. The atmosphere will be primed for heavy rain as well, but
unsure of the flash flood potential as it appears that individual
updrafts should be moving and the front steadily advancing. Even
still, plan to closely monitor the ongoing morning precipitation
closely in terms of its impact on afternoon/evening flood potential
and evaluate the potential for a flash flood watch a bit later this
morning.

There are suggestions that with the LLJ becoming largely parallel to
the frontal boundary late this evening into the overnight hours that
convergence will be minimized in the local CWA and convective
coverage may shrink as the night progresses despite an otherwise
favorable environment.

The early morning weather today...complex in its own right...
complicates the afternoon forecast a bit as well. With that in mind,
forecast confidence is near average, particularly regarding
convective coverage this evening and overnight...severe weather
potential...and associated rainfall amounts.

---------
UPDATED AT 510 AM REGARDING FLASH FLOOD POTENTIAL...
Continue to evaluate flash flood potential this AM, not only with
current precip, but for afternoon thunderstorms. Current activity
has shown signs of general weakening, and unless any intense
training develops, the flash flood potential is quite low with the
exception of Cloud/Republic/Washington counties which have had a
significant amount of rainfall overnight and likely have a few
areas of minor small stream flooding ongoing. The morning precip
does set the stage for higher flood potential later today, but
current thoughts (as supported by WRF-ensemble and individual
HRRR/ARW/NMM runs) are that the front this evening will be
progressive enough and convective updrafts scattered enough that
widespread flooding potential is low. So, will hold off on a flash
flood watch for now, but should continue to monitor through the
day should the forecast change, especially given the high PWAT
values and fairly saturated soil conditions in place.

.LONG TERM...(Friday through Wednesday)
Issued at 318 AM CDT THU JUN 11 2015

Only made minor changes in the extended forecast, as the overall
pattern remains unchanged from previous guidance. Widespread severe
potential wanes during this period as wind profiles through the
column weaken.

On Friday morning, overnight convection may linger with the frontal
boundary across far east central areas. During the afternoon,
guidance depicts a broad southwest upper trough slowing entering
western Kansas. Meanwhile the frontal boundary becomes nearly
stationary from southeast KS through northwest OK. The latest ECMWF
and GEM differ slightly on the track of the PV anomaly being a tad
further east, generating thunderstorms in the afternoon over much of
the CWA. However, the GFS and NAM continue to show a more persistent
solution of a slower trend which would focus best precip chances
south of Interstate 70 in the afternoon, increasing northward across
northeast KS Friday evening and Saturday as the vort max lifts
through the CWA. Widespread showers and thunderstorms remain likely
Friday evening through Monday as weak PVA tracks directly through the
area. Rainfall should not be continuous for the entire time frame,
however saturated conditions in place suggest a moderate or heavy
round or two of rainfall would quickly yield flooding concerns.
Severe potential will be marginal given the weak capping inversion
each afternoon, and the warm, moist sfc conditions yielding high
CAPE values. Hail and gusty winds would be the hazards if this were
to occur.

With the departure of the weak trough on Sunday evening, the upper
low across the southern plains becomes cutoff as the main jetstream
resides over the northern plains. A cool front is expected to stall
over the CWA Monday and Tuesday, providing a focus for possible
showers and thunderstorms Monday through Wednesday. Total rainfall through
the period could likely accumulate between 2 to 4 inches, locally
higher for some locations.

&&

.AVIATION...(For the 12Z TAFs through 12Z Friday Morning)
Issued at 627 AM CDT THU JUN 11 2015

Scattered rain and a few thunderstorms will continue over TAF
sites through mid morning. Even with showers, expect predominant
VFR conditions with ceilings at 5000 feet and above. After morning
showers end, VFR will continue with southerly winds gusting to 25
kts by afternoon. A cold front will approach TAF sites between 23Z
and 01Z with scattered TS along the front. Winds turn out of the
NW with frontal passage and lower ceilings are likely to develop,
currently expected in the low end MVFR range although there is a
small chance for IFR cigs.

&&

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

UPDATE...Barjenbruch
SHORT TERM...Barjenbruch
LONG TERM...Bowen
AVIATION...Barjenbruch

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TOPEKA KS
603 AM CDT THU JUN 11 2015

KSZ008>012-020>024-026-034>040-054>056-058-059-121115-
REPUBLIC-WASHINGTON-MARSHALL-NEMAHA-BROWN-CLOUD-CLAY-RILEY-
POTTAWATOMIE-JACKSON-JEFFERSON-OTTAWA-DICKINSON-GEARY-MORRIS-
WABAUNSEE-SHAWNEE-DOUGLAS-LYON-OSAGE-FRANKLIN-COFFEY-ANDERSON-
603 AM CDT THU JUN 11 2015

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

.DAY ONE...TODAY AND TONIGHT.

THUNDERSTORMS WITH AREAS OF HEAVY RAIN WILL CONTINUE ACROSS THE
ENTIRE AREA THIS MORNING...GRADUALLY ENDING FROM WEST TO EAST BY
MID TO LATE MORNING. LOCALIZED FLOODING...PARTICULARLY OF SMALL
STREAMS AND POOR DRAINAGE AREAS...IS POSSIBLE WITH THE HEAVIEST
RAIN THIS MORNING.

SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG A COLD FRONT
BY MID AFTERNOON. SOME OF THESE STORMS MAY BECOME SEVERE...MAINLY
BETWEEN 3 PM AND 9 PM. THE PRIMARY HAZARDS WITH ANY SEVERE STORMS
WILL BE LOCALLY DAMAGING WIND AND LARGE HAIL. FLASH FLOODING WILL
ALSO BE POSSIBLE...PARTICULARLY WHERE MULTIPLE STORMS CAN MOVE
OVER THE SAME LOCATIONS.

FLOODING ALONG THE BIG BLUE RIVER NEAR BLUE RAPIDS IS FORECAST TO
PERSIST UNTIL FURTHER NOTICE.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.

PERIODS OF THUNDERSTORMS ARE POSSIBLE FRIDAY THROUGH WEDNESDAY AS
A SERIES OF DISTURBANCES MOVES THROUGH THE OUTLOOK AREA.
CERTAINTY IN SEVERE STORMS DEVELOPING AT ANY PARTICULAR TIME IS
LOW AS THESE SYSTEMS ARE FAIRLY WEAK GIVEN THE DECENT AMOUNT OF
INSTABILITY IN PLACE. MAIN HAZARD WILL BE THE BRIEF HEAVY
RAINFALL...LEADING TO LOCALIZED FLOODING.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON AND
EVENING...MAINLY IN NORTHERN KANSAS BETWEEN 3 PM AND 9 PM.
SPOTTERS ARE ALSO ENCOURAGED TO REPORT RAINFALL AMOUNTS GREATER
THAN AN INCH TO THE NATIONAL WEATHER SERVICE.

&&

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

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TOPEKA KS
745 AM CDT THU JUN 11 2015

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

0744 AM     HEAVY RAIN       2 SW MANHATTAN          39.16N 96.60W
06/11/2015  E1.22 INCH       RILEY              KS   PUBLIC

&&

BAERG

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TOPEKA KS
759 AM CDT THU JUN 11 2015

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

0757 AM     HEAVY RAIN       3 ESE JAMESTOWN         39.59N 97.81W
06/11/2015  E1.50 INCH       CLOUD              KS   TRAINED SPOTTER

&&

BAERG

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TOPEKA KS
804 AM CDT THU JUN 11 2015

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

0804 AM     HEAVY RAIN       MILTONVALE              39.35N 97.45W
06/11/2015  M1.04 INCH       CLOUD              KS   CO-OP OBSERVER

            24 HOUR TOTAL

&&

BAERG

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TOPEKA KS
809 AM CDT THU JUN 11 2015

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

0809 AM     HEAVY RAIN       E HANOVER               39.90N 96.87W
06/11/2015  E1.55 INCH       WASHINGTON         KS   TRAINED SPOTTER

&&

BAERG

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