Area Forecast Discussion
Issued by NWS Goodland, KS
FXUS63 KGLD 192007
Area Forecast Discussion
National Weather Service Goodland KS
207 PM MDT THU MAY 19 2016
.SHORT TERM...(This evening through Friday)
Issued at 1203 PM MDT Thu May 19 2016
Cloud cover is again limiting temperatures today as widespread CU
developed in the moist layer from 4-6kft AGL.
The main concern from this evening through Friday is the
possibility of fog developing with very light rain or drizzle
across mainly the eastern and central sections of the forecast
area after midnight. Overnight temperatures drop into the upper
40s to around 50 with dewpoints either remaining or increasing
into the upper 40s as southeast winds continue to bring moisture
into the central high plains region. Expect the boundary layer to
saturate and produce widespread areas of low clouds and fog with
some very light rain possible as weak lift being generated below
700mb as a weak mid level short wave trough lifts across the
eastern sections of the forecast area early Friday morning. Expect
fog and low clouds to remain in place through much of the morning
with breaks possible by mid day. High temperatures will be 5-10
degrees warmer than today.
.LONG TERM...(Friday night through Thursday)
Issued at 207 PM MDT Thu May 19 2016
For this extended forecast period, main focus continues to be the
threat of severe weather Saturday, Sunday and potentially Tuesday as
well. For now, Sunday appears to have the highest threat for severe
thunderstorms. It would not surprise me if a more significant severe
threat developed (hail greater than 2" in diameter, greater than 70
mph wind gusts, a few tornadoes) on Sunday.
Saturday will be the first day of potential severe weather. A
dryline forms over east Colorado Friday night, sliding east into
northwest Kansas and southwest Nebraska Saturday. By Saturday
afternoon, SBCAPE climbs well into the 1000-2000 J/KG range.
However, a few factors are working against Saturday`s severe threat.
First, morning stratus/drizzle/fog over portions of the region may
limit instability to a fairly narrow axis along the dryline. Second,
a stout inversion/high CIN is forecast by a few guidance members.
This makes sense given the likelihood of an expansive stratus field
limiting surface heating. Third, forecast guidance is not too
impressive with 0-6 KM Bulk Shear, only on the order of 25-35 kts.
While this is sufficient for storm organization and severe weather,
it doesn`t necessarily heighten the threat of widespread significant
severe. Overall, severe thunderstorms, including supercells, should
be anticipated...but expect them to be isolated/widely scattered.
Sunday is forecast to be the more impactful severe weather day
across the region. There could be two rounds of severe
thunderstorms. Round one will form along a dryline draped over
northwest Kansas and southwest Kansas. Ahead of the dryline, a moist
and highly unstable atmosphere will develop, characterized by SBCAPE
of 1500-3000 J/KG and 850-500 mb lapse rates of 7-8.5 C/KM. 0-6 KM
Bulk Shear also ramps up to 30-45 kts, indicating a highly sheared
environment. LCLs, depending on which guidance member you glance at,
are either quite favorable or unfavorable. 0-3 km Helicity ahead of
the dryline also increases significantly, up to 200-350 m2/s2.
Favorable hodographs are also a factor increasing confidence in
severe weather. All this being said, severe supercell thunderstorms
appear likely ahead of the dryline. All modes of severe weather
could be expected with these storms...including the potential for
hail larger than 2" in diameter, significant damaging winds and a
few tornadoes (possibly a strong one too). Later in the evening, a
cold front should surge south across the High Plains. This strong
forcing mechanism combines with remaining instability, leading to
additional thunderstorm development (round 2). This round would be
capable of large hail and damaging winds.
Finally, Tuesday is another possible day for severe thunderstorms. A
cold front should still be located over the Tri-State Region. In
addition, a low pressure is forecast to be over southwest Kansas.
Low level moisture should wrap around this surface low and advect in
behind the cold front. North of the cold front, temperatures should
be slightly cooler but still warm enough, when combined with rich
moisture, to produce a large amount of instability. Shear increases
ahead of a shortwave trough. As the shortwave moves through,
thunderstorms should develop. Unfortunately, guidance differs on the
timing of this shortwave trough, thus leading to large differences
in thunderstorm initiation timing. Severe weather does appear
probable and Tuesday continues to warrant a watchful eye.
.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 1133 AM MDT Thu May 19 2016
Gusty south winds will continue through the afternoon at MCK and
GLD and are expected to diminish around 00Z as the sun sets.
Conditions at MCK and GLD will start out VFR this afternoon and
transition to LIFR after midnight (approx 06-08Z) due primarily to
low ceilings expected to develop below 500ft AGL. LIFR conditions
overnight will transition through MVFR to VFR conditions again
between 16Z- 18Z on Friday as ceilings begin to dissipate and