Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/28/17

Area Forecast Discussion

National Weather Service Denver/Boulder CO

 825 PM MST Fri Jan 27 2017

.UPDATE...
Issued at 817 PM MST Fri Jan 27 2017

Water vapor imagery showing upper trof over far northeast Colorado
this evening and moving rapidly south and southeast. This
disturbance kicked off some moisture and even a few snow showers
on the far plains this evening. However, should see rapid clearing
over the plains for the overnight hours. Have adjusted forecast to
reflect these latest trends. Other change was to lower
temperatures tonight over the high mountain valleys with mainly
clear skies.  No other changes needed.

UPDATE Issued at 554 PM MST Fri Jan 27 2017

Increased winds slightly over the plains overnight following model
guidance trends. Current shortwave moving over the northern plains
should still only produce cloud cover, though there may be a
flurry or two over Phillips or Sedgwick counties according to
echoes on radar moving south out of Nebraska. Looking at dew point
depressions however would likely result in mainly virga. Added a
10 percent chance of seeing a few snowflakes.

&&

.SHORT TERM...(This evening through Saturday)
Issued at 110 PM MST Fri Jan 27 2017

A weak disturbance wl clip the northeast corner of Colorado this
evening in the 01-04z windows, with a drier northerly flow for
the rest of tonight and Saturday, as an amplified ridge over the
west coast. Will keep more cloud cover around this evening with
the passing system but no showers expected.  The HRRR does show
some weak echoes but do not expect this to add up to any pcpn.
Lesser cloud coverage thereafter. Main moisture around on
Saturday in the 600-400 mb layer. Gusty northerly winds will
continue above timberline on Saturday with ridgetop winds in the
35-40 mph range. Adjusted the low temperatures in the mountains
and high valleys based off the much colder temperatures this
morning. It will not be as cold but some places will still drop to
well below zero, -10 to -15F. Across the northeast plains, gusty
northwest winds will continue into early evening then taper off.
Saturday will remain dry and temperatures will continue to
moderate with a little more sunshine. Gusty northwest winds will
return to the far northeast plains by the aftn but not as strong
as today, with peak gusts around 30 mph.

.LONG TERM...(Saturday night through Friday)
Issued at 110 PM MST Fri Jan 27 2017

A north-northwest flow aloft will turn more northwesterly Monday
and an upper level ridge over the western states flattens and
shifts a little east. Gusty winds will be possible over far
northeast Colorado Sunday afternoon, otherwise dry and quiet
conditions are expected through Monday. Temperatures will climb
above normal for Sunday and Monday with readings in the 50s over
northeast Colorado.

Continued warm and dry conditions are expected for Tuesday and
Wednesday with a west-northwest flow aloft overhead. The ridge axis
finally shifts across Colorado late Wednesday. High temperatures
across northeast Colorado are expected to remain in the 50s.

A progressive westerly flow aloft will be over the western CONUS
Thursday and Friday. The ECMWF shows a wave embedded in the
westerly flow late Friday. Will have low pops for the mountains
for this system. A downslope flow will keep areas east of the
mountains dry. Temperatures are expected to remain above normal.

&&

.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 817 PM MST Fri Jan 27 2017

After a brief wind shift to the east and Northeast at KDEN, winds
will now shift back east through south through 06z. Skies have
cleared out, with a mid level deck of clouds mainly East of KDEN
for the next few hours. Some increase in high level clouds
expected again Saturday morning from the North.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

UPDATE...Entrekin
SHORT TERM...Cooper
LONG TERM...Meier
AVIATION...Entrekin




Area Forecast Discussion

National Weather Service Wilmington OH

 925 PM EST Fri Jan 27 2017

.SYNOPSIS...
Northwest flow aloft will allow for slightly below normal
temperatures into the weekend, with the potential for a few
flurries or light snow showers each day. The best threat for
snow showers will occur Sunday night as an upper level
disturbance moves through the Ohio Valley. High pressure will
build into the Ohio Valley providing drier weather by the
middle of next week.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
An 850mb shortwave is currently moving through the ILN CWA from
west to east, with a weak surface trough also apparent
underneath. Though not really evident on satellite imagery,
there is a definite min in 850mb theta-e depicted on 18Z NAM /
01Z RAP projections, roughly coincident with the wave. Ahead of
the wave, there has been continued weak ascent, leading to
flurries and light snow showers. Along the wave, wind gusts are
briefly picking up into the 25-30 knot range. Behind the wave,
subsidence is leading to a shut-down of any precipitation, and
(eventually) a back edge to the stratocumulus, currently
entering far western Indiana.

PoPs for light snow have been kept in the forecast for another
couple hours, but ending from west to east as the overnight
period progresses. Sky grids were also changed to allow for some
clearing, mainly in the far southwestern CWA. Based on current
T/Sky/Wind trends (and the slight increase in cold advection
currently occurring) min temps were dropped slightly, mainly in
the western half of the CWA.

Previous discussion >
Mid level shortwave which pivoted through the region, along
with steep lapse rates and favorable dendritic growth, led to
numerous snow showers today. With this shortwave axis shifting
east, expect precipitation to diminish during the late afternoon
into early this evening. Numerical models show another weak s/w
leading to an enhanced period of snow showers later tonight.
Solutions differ on exact timing, but expect best time from
about 04Z through 09Z. Low level moisture continues to hold on
with skies remaining mostly cloudy. Lows tonight generally in
the middle 20s.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
In the wake of mid level shortwave, expect a general dry period
Saturday with a good deal of clouds lingering. Temperatures
will be close to normal, with highs ranging from the lower 30s
northwest to the upper 30s southeast.

Next mid level shortwave to drop southeast though the Great
Lakes Saturday night/Sunday morning and into the Ohio valley
Sunday afternoon/Sunday night. Will ramp up snow shower pops
with the best chance Sunday afternoon into Sunday evening.

Temperatures continue to be at or a little below normal. Lows
Saturday night to range from the lower 20s north to the upper
20s south. Highs on Sunday generally upper 20s to lower 30s and
lows Sunday night upper teens northwest to middle 20s southeast.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
Models continue to show a long wave upper trough in place over the
eastern CONUS. This pattern will leave the ILN area under a
northwest flow aloft, providing little moisture, while main band of
forcing remains to the north.

A few snow showers may linger in eastern locations Monday behind a
departing short wave trough. Otherwise, skies will be mostly cloudy.
A chunk of short wave energy will develop a surface low over the
Great Lakes on Tuesday. This system will provide a chance for snow
showers across the north half of the FA.

For Wednesday through Friday, scant moisture and forcing associated
with a flattening upper flow over surface high pressure is forecast
to keep precip out of the area.

Temperatures start out chilly Monday with highs in the lower 30s. A
brief round of warm advection Tuesday is expected to boost readings
to around 40. Highs are then forecast to retreat back into the 30s
for Wednesday through Friday.

&&

.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
The chance for flurries (and possibly an MVFR snow shower) will
continue through the next few hours, before precipitation is
likely to come to an end going into the overnight period. While
ceilings are currently just above or below the MVFR threshold
(around 2500-3500 feet), a gradual drop in ceilings is expected,
with prevailing MVFR conditions overnight. The one exception to
this will be at KCVG, where a period of some scattering of the
clouds is expected late in the overnight and through most of
Saturday morning. Ceilings will likely become VFR at all TAF
sites during the mid-day on Saturday. However, MVFR ceilings
are expected again at all locations by Saturday night.

Winds will remain fairly steady through the period - out of the
WSW with occasional gusts to around 20 knots.

OUTLOOK...MVFR ceilings are likely from Saturday night through
Monday, with occasional MVFR/IFR visibilities possible in snow
showers. Some MVFR conditions are possible again on Tuesday.

&&

.ILN WATCHES/WARNINGS/ADVISORIES...
OH...None.
KY...None.
IN...None.

&&

$$
SYNOPSIS...AR
NEAR TERM...Hatzos/AR
SHORT TERM...AR
LONG TERM...Coniglio
AVIATION...Hatzos




Area Forecast Discussion

National Weather Service Melbourne FL

 857 PM EST Fri Jan 27 2017

.UPDATE...

...Below Normal Temperatures Through Early Next Week...
...A Cold Rain will Develop Saturday Night into Sunday...

Tonight...At the surface, a high pressure ridge extending along the
northern Gulf of Mexico coast will continue to provide a northwest
wind flow of cool/dry air.  Satellite was showing an extensive area
of mid clouds over the Gulf streaming eastward with a more narrow
band extending across central Florida. The low temperature forecast
hinges on how much clearing out of these clouds occurs.

Surface dew points remained quiet low this evening with values in
the 30s and 40s but the cloud cover was keeping temperatures several
degrees above forecast values in most areas.  The HRRR model shows
moisture fields will support diminishing cloud cover, especially
across the north half.  There is low confidence in this since recent
satellite trends suggest otherwise.

Have raised cloud cover some and only nudged temps up a degree or
two, thinking that there will be cloudy periods and a few clear
periods, which should allow temperatures to fall into the 40s
areawide.

...Previous Discussion...

Sat...Cold air advection will produce below normal temperatures with
highs ranging from around 60F Lake/Volusia to the upper 60s in
Martin county. More sun than clouds in the morning will give way to
top-down moistening as mid level moisture increases ahead of an
approaching shortwave trough. No rain is expected during the day but
skies may become overcast with altocumulus by sunset across the
north.

Sat Night-Sun Night...Increasing moisture across the area
combined with ample shortwave/jet stream energy aloft will promote
higher rain chances (prolonged light rainfall event) across ECFL.
A cold front will pass through the area Sun night and take
precipitation chances with it eastward. It will be a cold rain
(for east central Florida) with temps Sat night in the 40s. Sun
will be cool and damp, even raw for Florida, with overcast skies
and on and off showers especially in the morning. Some drier air
should move into northern sections (north of Orlando) during
Sunday afternoon but a high overcast should keep skies cloudy.
Highs on Sat and lows Sat night/Sun night will average 7-15
degrees below climo areawide.

&&

.AVIATION...
VFR through 00Z/29. West to Northwest winds 5 to 10 knots.

&&

.MARINE...
Tonight/Sat...A slight tightening of the pressure gradient is
indicated late tonight as a ridge builds along the Gulf coast while
a broad frontal trough over the Atlantic only moves slowly away.  So
a northwest wind flow at 15-20 knots should develop in the open
Atlantic and continue into Sat morning.  A diminishing of winds is
forecast Sat afternoon, but exercise caution statements will likely
be headlined for the early morning hours offshore north of Sebastian
Inlet.

&&

.MLB WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...None.

&&

$$

SHORT TERM...Lascody
IMPACT WX....Glitto