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Area forecast discussion 
National Weather Service Hastings NE
654 PM CDT sun Sep 14 2014

Short term...(this evening through monday)
issued at 319 PM CDT sun Sep 14 2014

Primary forecast concern lies with precipitation chances
overnight.

Hasnt been any notable changes in the upper level pattern...with
data showing flow remaining mainly nwrly...as high pressure
extends across the Southern Plains and Gulf Coast region...and
disturbances over Canada keep the northern Continental U.S. Under broad troughing.
Satellite imagery shows one shortwave disturbance currently making
its way through the northern rockies...will be the feature of interest
through the short term period. Outside of a few sprinkles
potentially hitting the ground in NC Kansas...conditions across the
County Warning Area have been dry this afternoon...with variable sky cover. At the
surface...the County Warning Area is being affected primarily by deepening low
pressure over eastern portions of Colorado...resulting in srly winds...which
have been gusty at times across western areas. Temperatures so far have
climbed into the upper 60s to middle 70s.

That above mentioned upper level shortwave disturbance will
continue to make its way generally southeast through the
overnight hours tonight...with the southern fringe of the trough axis
swinging through the Central Plains. There really hasnt been much
change in the 12z models...which continue to vary with how much/if
any thunderstorms actually develop/affect the County Warning Area as it swings
through. With the disturbance moving through and increased lift
along the nose of a 30- 40kt low level jet...certainly cant rule out
thunderstorms developing...but the most recent hrrr/rap/4km show
very little happening. Kept probability of precipitation similar to what was
inherited...low probability of precipitation this evening increasing to the 30-40 percent
range around midnight and after. Models/forecast soundings do
continue to show the lowest levels of the atmosphere moistening up
with time this evening/overnight...and will continue to mention
the chance for drizzle across the County Warning Area. Should thunderstorms
develop...models still showing the potential for at least modest
elevated instability...and with deep layer shear values shown to
be in excess of 40 kts...cant rule out some strong thunderstorms
and will keep mention going in the severe weather potential statement.

The accompanying surface cold front is expected to have pushed through
the majority of the County Warning Area by sunrise tomorrow...ushering in gusty
north winds. Have some lingering low probability of precipitation and drizzle in during
the morning hours...but activity should quickly exit the County Warning Area to
the southeast...with the remainder of the day dry. Looks to be a nice
afternoon...expecting diminishing cloud cover /though as the sun
comes out cumulus could develop/...wind speeds tapering off as surface high
pressure builds in...and highs in the middle 60s to near 70 degrees.

Long term...(monday night through sunday)
issued at 319 PM CDT sun Sep 14 2014

Guidance suggests quasi-zonal to northwesterly upper tropospheric
flow will be noted over the Central Plains to start the long-term
forecast period. Northwesterly upper tropospheric flow is then
expected to dominate through Thursday as upper tropospheric
ridging strengthens over the western Continental U.S.. upper tropospheric
flow is then expected to become quasi-zonal starting Friday as the
ridge shifts east and weakens somewhat.

An overall lack in Omega should promote dry conditions to the area
Monday night and Tuesday. Tuesday night...guidance suggests the
axis of a ~25kt jet streak just above the boundary layer will
promote enough thermal advection for precipitation production
across the southern two-thirds of the County Warning Area...a solution supported
by quantitative precipitation forecast fields from the operational GFS and ec...and to a lesser
extend the NAM. Went ahead with 20-30% probability of precipitation across roughly the
southern two-thirds of the County Warning Area Tuesday night into Wednesday as a
result.

Heading into Wednesday night...the development of another ~25kt
jet streak just above the boundary layer cold promote
precipitation across most any of the County Warning Area...a solution supported by
quantitative precipitation forecast fields from the operational GFS and ec. Allblend provided
20-30% probability of precipitation across the area and these probability of precipitation were left unchanged for
the most part.

The passage of an upper tropospheric short wave is then expected
to bring yet another chance for precipitation to the area Friday
night through Saturday night and allblend responded by providing
20-50% probability of precipitation to the area.

Forecast soundings from across the County Warning Area on Tuesday night...per the
NAM and operational GFS...suggest parcels rooted to between
700mb 800mb will have ~1500j/kg of potential energy to work
with...along with deep-layer bulk shear values of ~35kts. Given
this...will go ahead and outlook the potential for nickel-size
hail Tuesday night into early Wednesday morning.

Persistent southerly flow through the boundary layer and resultant
thermal advection should allow for a warming trend during much
of the long-term forecast period...with highs starting in the 60s
and low 70s on Tuesday but warming into the 70s and 80s to finish
the forecast period. Overnight low will likely start in the 40s
early Tuesday morning...but warm into the 50s and 60s to finish
the forecast period.

&&

Aviation...(for the 00z tafs through 00z Monday evening)
issued at 626 PM CDT sun Sep 14 2014

Convection is firing up across eastern Colorado...and latest
model data is maintaining some of this convection as it tracks
east through the evening and overnight hours...ahead of an
approaching cold front and increasing low level jet. As a result...
continued with the chance for a thunderstorms in the vicinity after about midnight
tonight...with ceilings lowering to MVFR levels over the next few
hours as clouds continue to thicken and lower. Winds will
transition and become northerly behind the aforementioned front
early Monday morning...with some light drizzle as well as IFR ceilings
expected to develop just before sunrise. Otherwise...once the
front pushes south of the local area...ceilings should lift and
clear...with VFR conditions and light northerly winds to 10 kts
expected at both sites after about 15/15z.

&&

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

$$

Short term...adp
long term...Bryant
aviation...Rossi

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