Area forecast discussion
National Weather Service Hastings NE
706 PM CDT Wednesday may 22 2013
Update...
issued at 703 PM CDT Wednesday may 22 2013
Made minor adjustments to the hourly forecast for this evening.
Forecast is pretty much on track.
&&
Short term...(this evening through thursday)
issued at 351 PM CDT Wednesday may 22 2013
Morning upper air analysis indicates a middle level low between the
northern Missouri River valley and the upper Mississippi
Valley...with subtle middle to upper level ridging over the Rocky
Mountain range...and a middle to upper level low over the
northwestern Continental U.S.. middle to upper level jet energy extends from the
west-central Continental U.S....east/southeast across the southern Continental U.S. And
then north/northeast into the Great Lakes region and southeastern
Canada. Middle and upper level flow is fairly weak over our area as a
result...maxing out at between 30 and 40kts near 400mb...per 12z
sounding data from klbf and koax. Water vapor imagery also shows
the middle level low between the northern Missouri River valley and
upper Mississippi Valley...and the middle level low over the
northwestern Continental U.S.. increased middle level moisture is also noted
extending from the southern/southeastern Continental U.S....northward into
the Ohio River valley and Great Lakes region. Middle level moisture
over the Central Plains however is fairly lacking. At the surface
a ridge of high barometric pressure exists across portions of the
northern and Central High plains...and an area of low barometric
pressure is noted across portions of the upper Mississippi Valley.
The low level wind field across our area remains from the
northwest as a result.
Guidance suggests the middle level low...currently to our east...will
continuing moving east tonight into tomorrow. The subtle middle to
upper level ridge...currently over portions of The Rockies...is
expected to overtake our area and the resultant lack in kinematic
forcing should provide dry conditions...and nothing in the way of
high-impact weather...to our area through the next 24 hours.
Little change in the low level airmass suggests similar high and
low temperatures will be observed across our area tomorrow when
compared to today. An overnight low in the 40s is forecast for
most locations tonight...with a high in middle 60s to low 70s on
Thursday...as a result.
Long term...(thursday night through wednesday)
issued at 351 PM CDT Wednesday may 22 2013
This is messy and lower confidence long term forecast period. Are
going to be seeing periodic thunderstorm chances across the
County Warning Area...the big question lies with the timing...especially the
further out in time you go.
Looking at the upper level pattern at the start of the
period...models are in pretty good agreement. The plains are under
the influence of an ridge axis extending well into
Canada...basically sandwiched between a trough over the eastern third
of the Continental U.S....and a low pressure system parked over the Pacific northwest.
Through the rest of the forecast period...the basic idea remains
the same...with some variation of that ridging remains in place
over the area...depending on the model. With low
pressure/troughing anchored over the western Continental U.S....will see periodic
waves of energy ejected out through The Rockies and onto the
plains. The first of these waves looks to affect the region late
Thursday night and into Friday...with additional precipitation
chances coming basically each day after that as additional waves
move through.
At the surface...models showing that overall...the County Warning Area generally
remains between high pressure extending through the Great
Lakes/Midwest down to the Gulf...and varying strengthens of low
pressure over the Front Range/High Plains. On Friday /esp early in
the day/...drier air associated with the area of high pressure
over the Minnesota/WI area will keep dewpoints down a bit...but once that
high slides east and the pressure gradient tightens up as the low
deepens to the west and the southerly flow picks up...models in
good agreement showing increased dewpoints for the rest of the
period. Along with the dewpoints will be increasing amounts of
instability...more for Saturday and beyond than Friday. So has
been mentioned previously...strong/severe thunderstorms will
remain concern...especially so if we can get a surface boundary to
set up in/near the County Warning Area. One thing models do show is that overall
deep layer shear isnt overly impressive...but isnt on the
extremely low side either. Plenty of details to Iron out over the
coming days.
No significant changes were made to the temperatures...which
generally remain in the upper 70s to middle 80s range.
&&
Aviation...(for the 00z kgri taf through 00z Thursday evening)
issued at 703 PM CDT Wednesday may 22 2013
This will be a tricky ceiling forecast as some ceilings upstream
are in the MVFR range. Difficult to tell how long this will last
before the ceilings move off to the east...so confidence is not
the highest.
&&
Gid watches/warnings/advisories...
NE...none.
Kansas...none.
&&
$$
Update...heinlein
short term...Bryant
long term...ado
aviation...heinlein
