Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Hastings NE
1207 am CDT Friday Oct 31 2014

Short term...(this evening through friday)
issued at 405 PM CDT Thursday Oct 30 2014

A brisk but seasonally above average day temperature-wise across the
area. Forecast area sitting in between two frontal boundaries...the
first passing last night and giving US the strong winds...the Second
Set to move through this evening/early overnight. Second front is
more of reinforcing shot of cold air...likely the coolest of the
season so far. Low clouds and solid surface pressure rises mark the
leading edge of the colder air moving south and approaching
northern Nebraska this afternoon.

The front will bring colder temperatures and a period of lower
clouds essentially. The good news is the low clouds are primarily
moving through tonight/during the night...so sunshine by middle morning
Friday will take the edge off of sharply colder Halloween
temperatures. Winds will slowly turn northeast...east...southeast
through the day Friday and will gradually lessen as surface ridge of
high pressure extends across central and eastern Nebraska/Kansas.
Well advertised temperature drop is on target with highs in the 40s
for the most part. Morning lows in the 20s for most areas...although
a bit of a breeze overnight and clouds will keep the bottom from
falling out. No precipitation is expected with the frontal passage.

Late afternoon trick-or-treaters will want to be bundled up and
expect temperatures in the middle/upper 30s by sunset across the
region. Look for plenty of sunshine during the afternoon hours
with winds slowly dropping off.

Long term...(friday night through thursday)
issued at 405 PM CDT Thursday Oct 30 2014

To summarize this 6-day period in its simplest broad
perspective...precipitation-wise its dry the vast majority of the
time and temperature-wise its looking to average fairly close to
early-November normals...with daily highs somewhere in the 50s or
60s and overnight lows mainly in the 30s but also with a few
opportunities for colder 20s and slightly-milder 40s.

As for daily high temperatures...the current candidate for the overall-
chilliest of these 6 days is right away Saturday...while the
overall-warmest is probably Sunday...although early indications
are that next Thursday could have similar highs to Sunday in much
of the area. As for lows...the only night during which a
legitimate hard freeze looks like a decent good bet is Friday
night...meaning that for those limited portions of the County Warning Area mainly
in north central Kansas that have yet to see a hard freeze...and if
doesn/T already happen tonight as covered in the short term
above...then there is a good bet it will occur Friday night.

Precipitation-wise...although a few minor changes were made to pop
values and locations...its still the case that only 3 out of these
12 forecast periods (sunday night through Monday night) carry any
mention of rain shower potential...and even then its not mentioned
for the entire County Warning Area. Pending some fairly notable changes in
forecast models...this weather system is starting to look a little
like the one a few days ago that produced little to nothing within
the County Warning Area...and in fact the latest 12z European model (ecmwf)/GFS generally agree
that the best measurable rain chances would most likely skirt
around to both the northwest and especially just to the southeast
of the County Warning Area...with much higher rain chances/amounts favored along a
corridor from southern/eastern Kansas into MO/Iowa where moisture
availability will be noticeably greater.

As for any weather elements worthy of inclusion in the local
hazardous weather outlook (hwogid)...there continue to be none
worthy of inclusion. As always though...this is no guarantee to
stay this way. The first possible caveat here would be whether
future shifts might be inclined to throw in a limited risk of
thunderstorms with the early-week low pressure system as a few
neighboring National Weather Service offices have done. For now have stayed the course
from our past several forecast cycles and kept these precipitation
chances as generic rain showers...as although there could be some
weak convective instability around...its probably not Worth
"spoiling" an "empty" severe weather potential statement product yet in the day 4-5 time frame
as thunder can be inserted later if necessary. Otherwise...fortunately
for this time of year there are currently(key word currently) no
afternoons that warrant heightened fire weather concerns...as
despite some legitimately breezy days relative humidity values are
currently forecast drop no lower than 25-30 percent within the County Warning Area
on any given day...safely above the critical 20 percent threshold.

Getting in greater meteorological detail and taking it in 12-48
hour blocks...

Friday evening/night (halloween night)...as touched on
earlier there is decent confidence in this being the coldest
night of the valid long term period. For the evening trick-or-
treat crowd...temperatures will average in the 30s the first few hours
around/after sunset...but a decent chunk of the County Warning Area will probably
be in the 20s by 9-10 PM. Fortunately...confidence is essentially
100 percent in a dry night...as the middle-upper levels feature a
broad large scale ridge axis dominating the central Continental U.S....in
between broad troughs in the eastern/western Continental U.S.. meanwhile at
the surface...southeast breezes will actually be on a slight
increase as the night wears on thanks to weak pressure falls in
the wake of a ridge axis departing eastward into IA/MO. For the
night as a whole...southeast breezes should average 5-15
miles per hour...lightest in the evening and strongest toward sunrise. This
wind regime often helps hold low temperatures slightly above
expectations but given that skies should average mostly clear and
that temperatures won't have to drop very far from daytime highs to get
rather cold...opted to make little change here and aim nearly the
entire County Warning Area into the 23-28 range. For what its Worth these values
are slightly above raw 12z met/mav guidance values to account for
the mitigating breezes.

Saturday daytime-Saturday night...confidence remains quite high
in dry weather...although in the middle-upper levels flow will
transition from northwesterly to southwesterly as the leading
edges of the large-scale western Continental U.S. Trough starts to enter the
High Plains. Meanwhile at the surface...the number one story
Saturday will be chilly/breezy conditions. Do not let the raw
temperature values alone fool you. Temperature-wise...although
highs were generally lowered 2-3 degrees from previous
forecast and mainly only around 50 degrees..they still reflect
roughly a 10 degree increase versus Friday. However...it won't
feel much better (maybe worse) thanks to steady sustained
southerly breezes of 15-25 miles per hour and gusts generally 25-35 miles per hour.
Needless to say...these winds will keep a noticeable bite in the
air despite what should be mostly clear-partly cloudy skies.
Steady sustained south winds of 15-20 miles per hour with higher gusts will
persist through Saturday night...which along with slightly warmer
air moving in aloft should help keep low temperatures roughly 10 degrees
milder than Friday night...mainly in the middle-upper 30s range.

Sunday daytime-Sunday night...the forecast remains dry through the
day before a low-confidence 20 percent slight chance of rain
showers come in for most areas Sunday night. However...low-
confidence is the key phrase here as the latest European model (ecmwf) actually
keeps all rain potential northwest of the County Warning Area through the night as
well. In other words...Don/T be surprised if this slight chance
eventually gets pulled out in future forecasts depending on how
things trend. At the surface...although maybe not quite as windy
as Saturday...Sunday will again be breeze out of the south at
sustained speeds generally 15-20 miles per hour with higher gusts.
Fortunately...a modest increase in temperatures will occur as
well...and although highs were tweaked down very slightly from
previous forecast still have most areas rising back into the
60s...with far southwestern counties even low 70s.

Monday daytime-Monday night...low-confidence rain shower chances
are in place mainly within the eastern 1/2 of the County Warning Area as a large-
scale/broad positively tilted trough axis passes through the
central Continental U.S.. as earlier mentioned...barring substantial changes
the much better rain chances should target counties slightly
south-southeast of the County Warning Area leaving the local area mainly dry on
the fringes. That being said...do have a very small area of probability of precipitation
as high as 50 percent in the southeast corner of the County Warning Area in
Mitchell County Kansas. At the surface...a weak cold front passes
through but highs are still aimed into the upper 50s-middle 60s.

Tuesday daytime through Thursday daytime...this entire 60 hour
period remains void of precipitation mention to finish out the long term
period...and confidence remains fairly high in this for being 5-7
days out. In short...rather dry northwesterly flow returns aloft
to the Central Plains...riding around the edges of a large-scale
middle-upper ridge axis building into the western/central Continental U.S.
Behind the departing early-week low pressure system. Temperatures remain
quite seasonable for this time of year...with highs Tuesday
through Thursday gradually climbing from the 50s to the 60s.

&&

Aviation...(for the 06z kgri/kear tafs through 06z Friday night)
issued at 1137 PM CDT Thursday Oct 30 2014

A narrow band of MVFR cloud cover will shift south and west during
the overnight hours. With the band narrow and the clouds beginning
to break have kept clouds scattered but a couple hour period of
broken MVFR ceilings is not out of the question. Mainly clear skies
are forecast after daybreak. Northerly winds will remain steady
during the night but will subside and shift easterly Friday as the
surface ridge settles onto the plains.

&&

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

&&

$$

Short term...Moritz
long term...pfannkuch
aviation...Fay

National Weather Service Glossary of Abbreviations