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Area forecast discussion 
National Weather Service Hastings NE
1227 am CDT Monday Mar 30 2015

Update...
issued at 706 PM CDT sun Mar 29 2015

The red flag warning has been allowed to expire at 7 PM as wind
speeds will become light during the evening/tonight...and relative
humidity values will increase as temperatures cool.

&&

Short term...(this evening through monday)
issued at 249 PM CDT sun Mar 29 2015

Aloft: deamplification was of the flow was underway. Northwest flow will
remain over the Central Plains through tomorrow...with a lower
amplitude ridge over the western USA and a trough over the east.

Surface: high pressure was building in and will slide across the forecast
area this evening before departing into the southeast states. Tomorrow
a surface trough will move through in the warm sector of low pressure over the
Canadian prairies.

Tonight: quiet with good radiating conditions. A few multi-
layered middle-high clouds will move in from the northwest and skies should
gradually turn p/cloudy some areas after midnight.

Mon: a few clouds in the morning then clearing. Warmer by 15f.
Highs were increased above the previous forecast.

Used mix-down tool with GFS and forecast soundings to drop dewpoints
below most guidance.

Hwo: have added near-critical fire weather conditions for the southeast half
of the forecast area...for a few hours of gusty SW winds ahead of the
trough.

Long term...(monday night through sunday)
issued at 249 PM CDT sun Mar 29 2015

Guidance suggests upper tropospheric ridging will be noted over
the western Continental U.S. To start the long-term forecast period at 00z
Tuesday...with troughing over the east. Guidance also suggests the
western Continental U.S. Trough will advance east thus allowing for ridging
over our area Monday night through Tuesday night. As a
result...dry conditions are forecast across our area Monday night
through Tuesday night. Wednesday into Wednesday night...an upper
tropospheric trough axis is expected to approach from the western
Continental U.S....with a short wave also expected to move east across the
northern plains. Quasi- zonal to northwesterly upper tropospheric
flow is then expected to settle in across the region Thursday
Onward.

Although upper tropospheric thermal advection will increase
across the region with the approach of the longwave trough axis on
Wednesday...it does appear as though the short wave...and its
associated enhanced Omega...will remain north of our area. So it
appears as though widespread precipitation should remain more
confined to the northern plains and upper Mississippi Valley. That
said...guidance also suggests an area of low barometric pressure
will develop over south-central Canada ahead of the upper
tropospheric short wave. An associated boundary-layer baroclinic
zone is expected to extend south/southwest from this surface
low...with this baroclinic zone likely clearing our area Wednesday
into Wednesday evening. As this baroclinic zone clears our
area...guidance suggests boundary-layer convergence and a
weakening cap could result in isolated to perhaps scattered
convection across portions of the County Warning Area. This is a solution
supported by quantitative precipitation forecast fields from the NAM...operational GFS...ec and
sref-mean. Given all this...went ahead with 20-50% probability of precipitation across
much of the County Warning Area Wednesday evening. Guidance also suggests
boundary-layer moisture ahead of the baroclinic zone will climb
into the mid-50s. This boundary-layer moisture...working in
concert with increasing upper tropospheric lapse rates ahead of
the approaching trough axis...could result in significant
potential energy across the region Wednesday into Wednesday
evening. In fact...the NAM...operational GFS and ec all suggest
potential energy on the order of 1000-2000j/kg will be realized.
In addition...it also appears upper tropospheric jet energy could
help promote deep-layer shear values near 30kts. Given all
this...it certainly it appears hail production could be realized
with the stronger updrafts which are realized Wednesday afternoon
into Wednesday evening. Biggest question right now is just how
fast does the boundary-layer baroclinic zone clear our area on
Wednesday. Should it push through faster than currently
advertised...then it stands to reason that the boundary-layer
moisture will also be pushed east/southeast of our area thus
impeding deep updraft development. Given the fact we are still a
few days from this event...will hold off from a mention of severe
weather in the severe weather potential statement...but this is certainly something to monitor in
the coming days.

Its hard to get excited about precipitation chances beyond
Wednesday evening...however the operational GFS and ec both
suggest periods of enhanced upper tropospheric jet dynamics could
promote periodic light precipitation production. Superblend
responded by providing 20- 30% probability of precipitation across various portions of the
County Warning Area Thursday night into Friday...and these probability of precipitation were left
unchanged for the most part.

A very warm boundary-layer air mass will continue to promote warm
temperature readings across the County Warning Area Tuesday and Wednesday...with
guidance suggesting highs in the 70s and 80s will be realized. The
infiltration of a cooler boundary-layer air mass Post-frontal passage
Wednesday night should then promote highs generally in the 50s and
60s Thursday Onward. Overnight lows in the 40s and 50s are
currently expected Monday night and Tuesday night...with these
lows falling into the 30s to finish the forecast period.

&&

Aviation...(for the 06z kgri/kear tafs through 06z Monday night)
issued at 1225 am CDT Monday Mar 30 2015

A few middle to high level clouds are moving through the terminal
areas and will continue to through much of the day. Winds will
pick up from the southwest during the day and diminish again as
evening approaches.

&&

Gid watches/warnings/advisories...
NE...none.
Kansas...none.
&&

$$

Update...Fay
short term...halblaub
long term...Bryant
aviation...jcb

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