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Area forecast discussion 
National Weather Service Hastings NE
610 am CDT Wednesday Apr 23 2014

Short term...(today and tonight)
issued at 406 am CDT Wednesday Apr 23 2014

Satellite imagery showing the region coming under increasingly
southwesterly flow in the upper levels as the Main Ridge axis continues
sliding east...set up between an are of low pressure moving toward
the East Coast and a trough axis swinging through The Rockies. A
weak middle level disturbance out ahead of the main western
trough...working with warm air advection across the area thanks to
an increased low level jet...has resulted in some pretty scattered shower
activity early this morning. Mainly affecting the northestern two thirds
of the County Warning Area...there are a few lightning strikes here and
there...but instability is weak enough that it thunderstorms wont
be widespread. At the surface...the gusty winds continue...as the
County Warning Area sits with a tightened pressure gradient between high pressure
centered over the western Great Lakes...and low pressure over The
Rockies/High Plains. Southeasterly winds are generally ranging from 10 to
20 miles per hour /few closer to 25 mph/...and gusting at times between 25
and 30 miles per hour.

The main story with the forecast for today/tonight continues to
revolve around increasing thunderstorm chances. This
morning...will continue to see that area of scattered precipitation slide off
to the east...and by middle/late morning...most of the County Warning Area looks to
be dry. Currently expecting that to remain the case into at least
the early afternoon hours...though the hrrr/rap/4km WRF suggest it
may be fairly quiet through middle afternoon. Overall...there really
hasnt been any notable changes with the models in the past
several runs. Still expecting the upper level trough /associated
with a low pressure system over southwestern Canada/ to continue swing
east out of The Rockies and eventually onto the plains. At the
surface...the main area of low pressure ahead of the system is
expected to become better organized and set up over southeastern Colorado/southwestern
Kansas by middle afternoon. A cold front will be making its way south
into western/central Nebraska during the afternoon hours...while a
dryline is developing from western Kansas into western Texas. Ahead of the
front...still expecting to see a breezy/windy day across the
County Warning Area...and while there is some disagreement between models/guidance
with how strong winds will get...am keeping the current Wind
Advisory as is.

For our County Warning Area...this cold front will be the primary focusing
mechanism for thunderstorm development. Maybe a few slight
variances...but models are in decent agreement showing initiation
occurring over the west/northwestern third or so of the County Warning Area middle/late
afternoon along the front...maybe closer to 00z if you believe
some models. The more widespread coverage of precipitation and higher
probability of precipitation arrive and spread east across the County Warning Area after 00z...with the
main time frame looking to be through midnight or so...with models
then showing a good push east through. Some suggest after 09z
there isnt much left around in our County Warning Area...we will see if it really
moves out that quickly.

One question that has been around the past few days and remains even
now is with the dewpoints/low level moisture. 24 hours ago...thought
that dewpoints would be more widespread lower 40s or so by
now...but they arent. 4 am observation are showing low/middle 30s across
most of the County Warning Area...with an ob or two closer to 40. Looking to the
south of the County Warning Area..dewpoints dont hit 50 until you get to the southern
half of OK. We are going to have good srly flow during the daytime
hours ahead of the cold front...but there is some work to do to
get those increased dewpoints this far north. Still have some
Lower/Middle 50s making their way into mainly eastern portions of the County Warning Area
late this afternoon/evening...but confidence is not high...with
some guidance suggesting some locations may be lucky to hit 50.
Made little change to the highs for today...ranging from the middle
70s east to lower 80s SW. Models still showing the potential for
decent amounts of instability to develop...but thats going to
depend on how much moisture gets up here. Feel the potential for
strong/severe thunderstorms remains...and we remain outlooked by
Storm Prediction Center...with the day 1 slight risk covering the entire County Warning Area. Agree
with the assessment that large hail/damaging winds would be the
primary hazards with activity that develops later today...and will
keep mention going in the severe weather potential statement.

Long term...(thursday through tuesday)
issued at 406 am CDT Wednesday Apr 23 2014

Preceded by 2 or 3 reasonably nice days...the main story in the
extended is the emergence of a large trough of low pressure onto
the plains Sunday... and the subsequent cooling trend and
precipitation chances.

Initially...Thursday through Saturday are pretty nice days for the
most part as shortwave ridging traverses the area. On
Thursday... temperatures will rebound nicely despite cooling after
the front and rain thanks to down sloping west northwest winds.
The main issue Thursday will be the potential for fire weather
concerns. Surface dewpoints have the potential to tank further
than current forecast similar to the Monday. Good mixing will push
winds into the 20 miles per hour range...and when combined low relative
humidity it will be very close to extreme fire weather conditions.
This will have to be watched as it teeters on the edge and not
completely certain.

Friday looks like a nice day. Weak surface trough slinks into the
area and winds will drop off. Skies will be partly to mostly sunny
and temperatures should warm nicely. Have nudged up temperatures a
good 5 degrees from previous forecast to account for the area
being in the dead center of the upper level ridge. Saturday is a
day of transition with more clouds likely as middle level thermal
gradient tightens up by afternoon ahead of the large upper level
trough. Increasing east to southeast wind will also make it feel a
bit cooler despite temperatures likely above normal by at least a
few degrees. Much of the day should be dry but can/T rule out an
isolated shower/storm and a slight chance of rain is in there.

The crux of forecast is really Sunday through Tuesday. No doubt a
large and deep upper level trough will set up over the Central
Plains as it is cut off from the main upper flow. It will hang
around in the region for several days next week. There are some
model differences...especially with the location of the upper
level low pressure by late Sunday. European model (ecmwf) has been furthest
north...but shifting south a bit with the 00z run closer to the
GFS/Canadian. The position is in important because if it does
translate further north...much of the forecast will experience
more of dry slot and less precipitation through Sunday night. If
the low is further the fetch of moisture will be more favorable
and the forecast area may receive more needed rain. Positioning
will also impact the temperature regime and when we cool down more
significantly...which appears to be most likely Monday and
Tuesday. Made few changes to the given extended forecast grids
with uncertainty in specifics at this point. The forecast reflects
30-40 percent average precipitation chances as a result.

&&

Aviation...(for the 12z tafs through 12z Thursday morning)
issued at 604 am CDT Wednesday Apr 23 2014

No significant changes made for this taf period...with main
concerns remaining with gusty winds and precipitation chances. Had
an area of scattered showers/isolated thunder move through in the past
few hours...but that activity has shifted east...and am currently
not expecting any additional precipitation until later this afternoon.
Didnt change the timing...still looking at late afternoon for
activity to potential move into the terminal area...and will keep
mention going with thunderstorms in the vicinity until things actually develop and can get
a better idea of timing/location. Thinking activity should slide
off to the east somewhere around midnight. Otherwise...a majority
of the period will have gusty S/southeast winds...with speeds increasing
late this morning into the afternoon into the 25 to 30 miles per hour
range...with higher gusts. A cold front will move through the
terminal area this evening...ushering in a switch northwest winds.

&&

Gid watches/warnings/advisories...
NE...Wind Advisory until 8 PM CDT this evening for nez040-041-047>049-
061>064-073>077-083>087.

Kansas...Wind Advisory until 8 PM CDT this evening for ksz005>007-017>019.

&&

$$

Short term...ado
long term...Moritz
aviation...ado