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Area forecast discussion 
National Weather Service Hastings NE
546 am CDT Friday Jul 25 2014

Short term...(today and tonight)
issued at 422 am CDT Friday Jul 25 2014

Biggest challenge will be determining high temperatures and heat
index today...and also chance of showers and thunderstorm this
evening in the southern County Warning Area.

The subtropical ridge continues to dominate the Central
Plains...giving US plenty of warm weather and will continue to give
US a healthy cap. A cold front will nudge south through the County Warning Area
today...which will make highs a bit tricky. There should be a fair
amount of compressional warming just ahead of this front today and
also some moisture pooling as well. This will create a scenario of
elevated heat index...especially in our south. The front will slow
down a bit...but should clear the County Warning Area before it stalls. However...we
could get some elevated convection just north of the stalled surface
boundary tonight...so I included a slight chance of showers and
thunderstorms as numerical models are hardly in agreement. Went
closer with consraw for highs and allblend for lows tonight...which
is close to the previous forecast.

Long term...(saturday through thursday)
issued at 422 am CDT Friday Jul 25 2014

Primary forecast concern through the long term lies with
thunderstorm chances.

At the start of the period...models showing the main area of high
pressure in the upper levels centered over nm/northern TX/OK...with ridge
flattened thanks to an area of low pressure sliding through central
portions of Canada. Our general area is set up in between this two
systems...resulting in more zonal flow. Confidence in the first 24
hours of the forecast is not high...mainly regarding precipitation
chances. Some models are showing the potential for a weak shortwave
disturbance /out ahead of the main system to the north/ moving
through the Central Plains Saturday morning...and some question
remains with whether this will result in any precipitation across at
least a portion of the County Warning Area. Cant completely rule out activity mainly
over northern portions /concerned about better capping further south/...so
have some probability of precipitation in the forecast...which are pretty low considering
the lack of good agreement among models.

Should things affect the area during the morning...expect that there
would be a break at some point into the early afternoon
hours...before chances for another round of thunderstorms works its
way in. The above mentioned upper level low over central Canada is
shown by models to slide southeast during the daytime Saturday and
into the overnight hours...ending up roughly over northern Minnesota by 12z
Sunday. A surface cold front is expected to be pushed south into
the region by this system...and would help to provide additional
focus for thunderstorm development. Unfortunately plenty of model
differences continue...with some not showing much of
anything...others keeping it confined to north/northestern portions /on the
edge of stronger capping...so again kept probability of precipitation on the lower side.
Cant rule out strong/severe thunderstorms given the
shear/instability combo.

As this upper level system continues its trek east through
Sunday/Monday...the pattern becomes more amplified...with the ridge
axis extending back north through The Rockies and into western
Canada...putting our area back in northwesterly flow. No notable
disturbances look to slide through the area during this period...so
the forecast remains dry.

More uncertainty returns to the forecast as we get into the middle
portions of the work week...and confidence is low. The region
remains in northwesterly flow in the upper levels...with models
showing more potential for periodic disturbances working their way
through and bringing additional thunderstorm chances. Current
forecast has multiple periods of probability of precipitation...but confidence in removing
them from any particular one is just not high enough at this
point...but would expect adjustments as that time gets closer and
models come into better agreement.

As far as temperatures go...Saturday is tricky with a daytime
frontal passage. Better mixing potential and warmer air along/ahead
of the front while cooler air starts to advect in behind makes
things difficult. Current forecast calls for near 90 in the north
with near 100 in the south...but any changes in model timing would
likely result in temperature adjustments. Once this weekend system/front
moves through and we return to northwesterly flow aloft...the County Warning Area is
set up between the coolest air centered over the Great Lakes/Midwest
and the warmest air over the western third or so of the Continental U.S.. this
looks to result in multiple days of highs near/slightly below
average for this time of year. Monday/Tuesday highs currently forecast in
the Lower/Middle 80s...with middle/upper 80s by Thursday.

&&

Aviation...(for the 12z tafs through 12z Saturday morning)
issued at 543 am CDT Friday Jul 25 2014

Biggest concern is low-level wind shear very early this morning.
Also...wind will eventually veer as a cold front approaches from
the north. VFR conditions are forecast. Any thunderstorms may
develop south of the terminals...closer to the front to the south.

&&

Gid watches/warnings/advisories...
NE...heat advisory from noon today to 7 PM CDT this evening for
nez063-064-074>077-083>087.

Kansas...heat advisory from noon today to 7 PM CDT this evening for
ksz005>007-017>019.

&&

$$

Short term...heinlein
long term...ado
aviation...heinlein

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