Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/17/18
Area Forecast Discussion
National Weather Service Binghamton NY
931 PM EDT Mon Apr 16 2018
.SYNOPSIS...
A slow moving upper level low pressure system will remain over
the area over the next several days. This will keep conditions
cool and unsettled, with mixed rain and snow showers. Temperatures
will be well below average early this week. A brief break in
the weather is expected on Wednesday with milder temperatures.
Another slow moving, cool storm system will impact the area
Wednesday night through the end of the week.
&&
.NEAR TERM /THROUGH TUESDAY NIGHT/...
Snow showers will continue moving northeast through the region
overnight. The snow is still mixing with rain in a few locations
but the changeover will occur by midnight as the 925 mb 0C line
still has not moved through eastern parts of our region. After
midnight, both the HRRR and RAP show diminishing coverage from
south to north so the evening update does indicate lower pops
the farther south you go. Snow accumulations overnight will be
light...mainly less than 1 inch and mainly over the higher
elevations of Central NY. Overnight lows will dip down into the
upper 20s to mid-30s.
The mid/upper level low pressure system will continue to spin
just northwest of Lake Ontario through the day on Tuesday. This
will bring much colder air aloft into the area on a brisk
northwest flow. Higher resolution models are indicating numerous
showers move through the area Tuesday afternoon, as a shortwave
disturbance rotates around the main low. With 850mb temps
between -6C to -9C, and fairly steep low level lapse rates,
expect convective type snow showers to be the rule. Cannot rule
out a few brief, heavier snow showers as well. With high
temperatures in the upper 30s to mid-40s much of the snow will
not accumulate during the day. Snow showers continue across
north-central NY Tuesday night...with some lake enhancement
likely. Another 1-2 inches are possible across northern Oneida
County, and the higher hills of Madison/Onondaga counties.
Meanwhile, the snow shower activity should diminish over NE PA
and the NY southern tier...with only slight chance PoPs or less
here. Another cold night, with lows in the upper 20s and 30s.
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
3 pm update...
An active period as a stacked cyclonic system moves east into
the area behind the departing storm from today.
The upper level trough that sets up over the northeast US
Tuesday keeps a moist northwest flow into the area into
Wednesday before lifting out late in the day. Typical spring
showers with snow or mixed in the morning changing to mostly
rain in the afternoon as surface temperatures rise. Highs mid
40s to lower 50s with the best chance of the light showers in
central NY.
Light showers ahead of the next system moves in Wednesday
evening. This system moves east from the Midwest through NY/PA
Thursday. Precipitation will start as rain then change to a mix
during the overnight as temperatures fall into the 30s.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
230 PM update...
A stacked low will be moving east through the area Thursday
causing the upper level trough over eastern New England to back
west into the area. The trough now lingers longer over the area
keeping the area cooler Saturday but probably dry. A cold
northwest flow will cause more light snow and rain showers for
Thursday to Friday night. Snow will be most likely at night.
Snow accumulations will be most likely at higher elevations on
grassy surfaces. Highs 40s to low 50s Thursday and Friday. Total
qpf with the system from Wednesday to Friday half inch or less
liquid. Snow amounts could be up to an inch each night at
higher elevations in CNY.
High pressure with some ridging aloft starts Saturday and
Saturday night, so that the high will be here Sunday and Monday.
Saturday has trended cooler with highs 45 to 55, but Sunday and
Monday close to normal with highs in the 50s. Low temperatures
throughout mostly upper 20s and 30s.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
00z update... As moisture continues to rotate around a deep low
pressure system close to the region, lower ceilings, and
occasional precipitation will continue this evening. Widespread
MVFR-IFR restrictions are expected, with alternate required
possible. Later tonight, slight improvement is anticipated, with
KELM and KAVP likely going back to VFR, and mainly MVFR-fuel
alternate at play elsewhere.
Other than the potential for a brief period of snow showers
early in the morning, we should see mainly VFR through 16-18z.
At least scattered snow showers/squalls are expected to develop
after 18-19z, in an unstable environment, with periodic IFR-
fuel alternate restrictions foreseen.
W-NW winds overnight (a bit gusty this evening), will be W-SW on
Tuesday, with somewhat more frequent gusts (particularly by
afternoon).
Outlook...
Tuesday night...Colder air moves in, along with rain or snow
showers, and probable restrictions.
Wednesday...VFR to start. Then restrictions possible in rain
showers late.
Wednesday night to Friday...Restrictions possible in rain and
snow showers.
Saturday...Chance of rain and/or snow showers, with brief
restrictions possible.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...None.
NY...None.
&&
$$
SYNOPSIS...MJM
NEAR TERM...MJM/MWG
SHORT TERM...TAC
LONG TERM...TAC
AVIATION...MLJ/MJM
Area Forecast Discussion
National Weather Service Grand Forks ND
1004 PM CDT Mon Apr 16 2018
.UPDATE...
Issued at 1002 PM CDT Mon Apr 16 2018
HRRR keeps any fog at bay. So will leave mention out. NAMNest does
have some fog in the far southern RRV but it is the only one. Thus
confidence remains low.
UPDATE Issued at 704 PM CDT Mon Apr 16 2018
Skies clear over the forecast area at 2330z. Fcst in good shape
and no changes needed. Will monitor for any fog potential in the
southern fcst area.
&&
.SHORT TERM...(This evening through Tuesday)
Issued at 302 PM CDT Mon Apr 16 2018
Temperatures and then the onset of precipitation Tuesday afternoon
will be the main concern for the period.
A brief quiet spell between systems tonight as the upper ridge
axis moves into the Plains. Skies will be mostly clear as the
clouds that have been hanging around our far eastern tier finally
pull eastward, and before the next round starts to move in. Winds
will shift around to an east to southeasterly direction as low
pressure develops over WY later tonight. Think there will be a bit
of mixing to offset clear skies. Have low staying in the 20s
across much of the CWA, with near 20 in the areas with more snow
cover. A couple of the high resolution models develop some fog
over southeastern ND where winds will be a bit lower, but am not
confident enough to include in the grids at this point. Will
monitor for an fog development. Think there will be enough
sunshine tomorrow to get into the mid to upper 40s in areas where
there is less snow, slightly cooler in the west central and
southeastern CWA with more white stuff hanging around.
Tomorrow, the next upper trough will begin to approach the western
Dakotas, with the main surface low well to the south over the
Central Plains. Southeast to east winds will continue to increase,
and several of the global models break out some light precip out
ahead of the main system and moving into our far western counties
later Tuesday afternoon. Think that it will take a while for
things to saturate, but can`t rule out a few sprinkles reaching
the ground before 00Z Wednesday. Included some low POPs in the
western Devils Lake Basin late Tuesday afternoon.
.LONG TERM...(Tuesday night through Monday)
Issued at 302 PM CDT Mon Apr 16 2018
Main body of the low pressure system looks to track south of the
area. Models in general agreement as to placement and movement. The
system is still forecast to bring a chance for a wintry mix late
Tuesday night into early Wednesday morning. Precipitation type will
vary based on temperatures and time of day, but overall any snow
amounts will be on the light side. Some light freezing
precipitation is possible but not expected to be widespread.
Behind the low...the ridge rebounds by Thursday and drier
conditions...along with warmer temperatures...will be on tap through
the weekend. Values are expected to be mainly in the upper 40s to
mid 50s...which is closer to climatological norms.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 704 PM CDT Mon Apr 16 2018
VFR thru the pd. A few fog patches may occur BJI/FAR areas but
attm confidence is low on coverage.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
UPDATE...Riddle
SHORT TERM...JR
LONG TERM...Hopkins
AVIATION...Riddle
Area Forecast Discussion
National Weather Service Hastings NE
926 PM CDT Mon Apr 16 2018
.UPDATE...
Issued at 924 PM CDT Mon Apr 16 2018
HRRR and RAP aren`t showing much potential for fog development
tonight. In fact, the latest RAP soundings continue to back off on
the potential for low stratus tonight into tomorrow morning as
well. As such, the mention of patchy fog has been removed from the
forecast.
&&
.SHORT TERM...(This evening through Tuesday)
Issued at 347 PM CDT Mon Apr 16 2018
Hazardous Weather Potential: None.
Aloft: A large shortwave ridge was over the Plains with a deep
trof along the W coast and a potent shortwave trof at its base.
The ridge will shift E of the rgn tomorrow as the Wrn trof presses
inland. The shortwave trof will become negatively tiled over CO
by 00Z/Wed.
Surface: High pres was over the Sandhills. This high will depart
to the E tonight. Meanwhile...a cold front was making its way thru
the Wrn USA. A warm front will form near the KS/OK border
tonight. Lee cyclogenesis will occur tomorrow over CO as the cold
front approaches. As this low ejects into Wrn KS...the warm front
will lift N but remain just S of the CWA.
Rest of this afternoon: M/sunny and cool. Highs will be about 15F
below normal.
Tonight: Increasing clds. Low stratus should form N of the warm
front and some light fog should also develop. Confidence is low in
the extent of the fog and modifications may be needed to better
reflect this potential. Near normal lows.
Tue: Lots of clds as the area will be N of the warm front. This
will hold temps down. Lowered highs from the prvs GID fcst and may
not have gone low enough. Could easily see most of S-cntrl Neb
remaining not getting out of the 40s.
.LONG TERM...(Tuesday night through Monday)
Issued at 347 PM CDT Mon Apr 16 2018
Hazardous Weather Potential:
- High winds possible Tue night
- Still windy Wed but not as strong
- Near critical fire wx conds Wed afternoon - SW counties
Aloft: The low that forms over IA Wed will depart with a ridge
moving thru Thu. The next low will move in off the Pac and slowly
meander thru the Desert SW Thu-Fri into the Srn Plns Sat. A
shortwave ridge should arrive by Sun.
Surface: The strong low over KS Tue night will head for the OH Vly
Wed with high pres building in thru Thu. Low pres will move well S
of the rgn into next wknd. GtLakes high pres should build in Sun-
Mon.
Winds: Have posted a High Wind Watch for our SW counties Tue night.
Am very concerned about high winds Tue night...and that is not
just in the watch area. The NAM/GFS/EC 850 mb winds are all 55-60
kt and CAA will probably keep mixing heights deeper than what fcst
soundings suggest. The watch is a conservative approach. The main
constraint at this time is that MOS winds aren`t there yet...and
the strongest CAA is SE of the CWA by the time the strongest winds
occur at 850 mb (around 12Z/Wed).
Even still...Wed will be a windy day wind NW 30G45 mph.
If RH`s end up a little lower in our SW counties in subsequent
fcsts...a Red Flag Warning will be required.
Temps: Continued below to much below normal. Sat will be the
coolest day.
Precip: Sct shwrs and a few tstms Tue night as the comma head
precip begins to develop N of the low. Accumulating snow has been
withdrawn from the fcst by the tool we use which uses a blended
thermal profiles...snow ratios and QPFs. However...an inch or two
could still occur on the back side of the precip shield as it
moves out (N of Hwy 92). This will be a quick-hitter. That snow
would really have to come down hard to accum over a short time
period.
The late week system will be a slow-mover which means we could see
multiple periods of precip potential (Thu night thru Sat night).
This is currently looking like primarily a rain event...but snow
is in the fcst and it is possible again...espcly in the nighttime
and morning hrs. The trend the last few days has been for this
low to drift further S than previously fcst. That means overall
less precip with the highest amts over our KS counties.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Wednesday)
Issued at 636 PM CDT Mon Apr 16 2018
Mid and high clouds continue to stream across central Nebraska
this evening.
Later tonight into Tuesday morning, some lower stratus is expected
to develop...but the extent/height of this is still a bit
uncertain. RAP/HRRR/GFS show a relatively brief window for reduced
ceilings late tonight into early morning, but the NAM is quite a
bit more aggressive and long-lived. This forecast takes the
"middle ground" with a longer window of MVFR ceilings, likely
rising to VFR by early afternoon, at the latest.
Short-term models aren`t showing much fog potential tonight, so
I`ve removed the BR mention from the TAFS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...High Wind Watch from Tuesday evening through late Tuesday night
for NEZ082-083.
KS...High Wind Watch from Tuesday evening through late Tuesday night
for KSZ005-006-017-018.
&&
$$
UPDATE...Mangels
SHORT TERM...Kelley
LONG TERM...Kelley
AVIATION...Mangels
Area Forecast Discussion
National Weather Service Lincoln IL
918 PM CDT Mon Apr 16 2018
.UPDATE...
Issued at 910 PM CDT Mon Apr 16 2018
The storm system that brought the rain and snow to the area over
the past 24 hours has finally shifted far enough to our east this
evening to allow winds to gradually subside. However, latest cloud
trends are suggesting a slower clearing trend aross the forecast
area tonight with the latest HRRR indicating the backedge of the
cloud shield out to our northwest rotating across parts of central
Illinois during the early morning hours. Will make some minor timing
adjustments to the sky condition for the early morning hours through
at least the mid-morning hours of Tuesday.
Surface high pressure will drift across the area on Tuesday bringing
some sunshine to the area and as a result, warmer temperatures.
Everyone should be back into the 50s Tuesday afternoon and that
will feel good compared with what he have had to deal with over
the past couple of days. But evening with the improvement in
temperatures tomorrow, we will still be around 10 degrees below
normal for the middle of April.
One concern related to the discussion above is with the HRRR forecast
soundings indicating some moisture getting trapped underneath a
developing subsidence inversion tomorrow resulting in more cloud
cover than currently forecast. The RAP soundings also hinting at
that possibility while the 3km NAM soundings indicated our eastern
counties may be in line for more cloud cover, at least through
the morning before the inversion starts to break down by afternoon.
Otherwise, the rest of the forecast looks to be doing fine with
very few changes made. An updated ZFP should be out soon with
adjustments to the overnight portion of the forecast, dealing
with the expected cloud trends across the forecast area.
&&
.SHORT TERM...(This evening through Tuesday)
ISSUED AT 309 PM CDT Mon Apr 16 2018
Upper low continues to pull away to the east with light rain/snow
showers diminishing from was to east. As showers are partially
diurnally driven, any lingering showers should end by sunset.
Currently this activity looks to be from around Bloomington to
Shelbyville eastward. Cold air will continue to advect into the area
in brisk northwest winds, with lows tonight from 25 to 30 degrees.
Winds will decrease and clouds will diminish as a high pressure
ridge axis to the west edges into the area. Will continue the freeze
warning for tonight along and south of I-70 where the growing season
has started, although even colder temperatures will be to the north.
Temperatures should start to moderate for Tuesday as high pressure
slips east and light or southerly winds begin. Expecting highs
ranging from the low 50s north of I-74 to the mid and upper 50s from
Springfield to Mattoon southward.
.LONG TERM...(Tuesday night through Monday)
ISSUED AT 309 PM CDT Mon Apr 16 2018
The next system of importance comes Wednesday as a fast moving upper
wave and attendant surface low ejects east from the Rockies. Models
are fairly consistent at this point with the surface low crossing
northern IL mid-day Wednesday. With the earlier timing, highs
Wednesday have trended downward as the warmest temperatures will
come early in the day before a cold front pushes east through the
area. Most of the precipitation looks to be north of I-74, although
have slight chances for rain from around Jacksonville to
Martinsville. Highs ranging from 51 in Galesburg to 68 in
Lawrenceville, although any earlier timing could trim those
temperatures down further. A few snow flakes will be possible
Wednesday night north of I-74, but no accumulation is expected with
lows just above freezing.
High pressure and dry Thursday and Friday. Highs low to mid 50s
Thursday then mid and upper 50s Friday. Next low looks to cut off
and move south of central Illinois over the weekend. Therefore,
have slight to no chance of precipitation and highs trending from
around 55 to 60 Saturday up to 60 to 65 Monday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 617 PM CDT Mon Apr 16 2018
The back-edge of the stratocumulus deck was near SPI at this hour
and will continue to slowly push east this evening. Based on the
current speed, it appears the clearing line will get to CMI by
05 to 06z. However, a few of the short term model solutions
suggest as the clearing line advances east late this evening,
additional clouds will develop just to the west and northwest
of the cloud shield after 05z, but confidence on that at this
time is low. Right now it appears if that did occur, it would
affect BMI and CMI by keeping the cloud deck (3000-4000 ft AGL)
in longer than currently anticipated. Will go more optimistic
at this point as high pressure builds into the region late
tonight and on Tuesday with VFR conditions. West to northwest
winds of 10 to 20 kts this evening will quickly diminish after
00z with a northwest wind of 10 to 15 kts expected on Tuesday.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
Freeze Warning from midnight tonight to 9 AM CDT Tuesday for
ILZ062-063-066>068-071>073.
&&
$$
UPDATE...Smith
SHORT TERM...37
LONG TERM...37
AVIATION...Smith
Area Forecast Discussion
National Weather Service Phoenix AZ
845 PM MST Mon Apr 16 2018
&&
.SYNOPSIS...A weather system moving across the western U.S. will
bring increasing breeziness, areas of blowing dust, and elevated
to critical fire weather conditions to the region. A significant
but short-lived cooling trend will occur into Tuesday, before
temperatures warm back to near seasonal normals midweek. A second
dry storm system will affect the Southwest Thursday and Friday,
bringing another round of breeziness to the region along with a
slight cooldown.
&&
.DISCUSSION...
A rather deep/cold upper low (for Mid-April) and associated sfc cold
front that is now moving across SE CA are helping to mix strong
winds aloft down to the sfc this evening across that region, with
wind gusts as high as 50 mph being reported at this hour. These
strong winds are also producing some blowing dust at this time
across the Imperial Valley, with visibilities briefly as low as 1/2
mile being reported. On the other hand, winds across South-Central
have been lighter then was was expected, likely due to thick
mid/high cloud cover inhibiting heating/mixing across the region
this afternoon. Latest high-res HRRR output is showing that winds
should slowly subside later tonight as nocturnal cooling allows the
boundary layer to decouple somewhat from the stringer winds aloft.
Winds are then expected to diminish further on Tuesday as the upper
trof/strongest winds aloft begin to shift off to the east.
&&
.PREVIOUS DISCUSSION...
Latest water vapor imagery shows a well-defined vort max near the
Bay Area. Meanwhile, thick mid and high clouds out ahead of the
upstream shortwave trough have persisted across the Desert
Southwest this afternoon. Latest radar imagery shows some weak
returns, but with dewpoints generally in the teens, it is unlikely
that any precipitation is reaching the ground. Virga is possible
with this cloud deck and given the dry sub-cloud environment,
isolated pockets of gusty winds/downdrafts will result.
The cloud cover has also inhibited insolation and mixing, so the
pressure gradient winds have not been realized just yet. However,
latest runs of the HRRR continue to indicate that windy conditions
will develop, particularly across southeastern California and
portions of Pinal County. These are dust prone areas, and there
certainly is the potential for patchy blowing dust during the
period of peak winds into this evening.
A significant cooldown into Tuesday can be expected as a cold
front moves eastward overnight. Highs 5-8 degrees below normal can
be expected, with highs in the upper 70s forecast across the
lower deserts. Transient shortwave ridging will build across the
region by mid-week, before a deeper and slower-moving storm system
evolves along the Pacific coast. Moisture will still be lacking
west of the Continental Divide, with the primary effect being
another increase in winds on Thursday/Friday and a minor cooldown.
With limited moisture, precipitation chances will remain low
across most of the forecast area, but a very slight chance of
showers may clip southern Gila County Friday afternoon and
evening. A general weakening of westerlies aloft is forecast to
occur in the wake of the departing storm system into next weekend,
resulting in another warming trend and perhaps a more prolonged
period of weaker wind speeds across the Southwest.
&&
.AVIATION...
South-Central Arizona including KPHX, KIWA, and KSDL:
A weather system passing to the north is expected to keep winds
going from a westerly direction through the rest of tonight and
through Tuesday. Drier air moving in from the west is expected to
clear out the mid/high clouds that are now being seen over the
region this evening.
Southeast California/Southwest Arizona including KIPL and KBLH:
Strong and gusty westerly winds and areas of blowing dust will
continue to be a serious aviation weather concern through the rest
of this evening with sustained WSW speeds over 20 kts and gusts as
strong as 45 kts. Winds are then expected to greatly diminish later
tonight and early Tuesday as the sfc cold front now affecting the
region moves off to the east, but with suspended dust likely
degrading slantwise visibility into Tuesday morning.
Aviation Discussion not updated for amended TAFs.
&&
.FIRE WEATHER...
Thursday through Monday:
Typical springtime conditions will continue with periods of breezy
to windy conditions as well as rather low minimum humidities,
modest overnight recovery and no chance of precipitation. Thursday
will be the next day of most concern, with RH and wind flirting
with critical thresholds. At this time, the higher terrain of
south- central AZ has the best chance of reaching thresholds with
more marginal potential elsewhere. Thereafter, latest guidance
suggests a warming trend with above normal temperatures returning
by Saturday and continuing into early next week.
&&
.SPOTTER INFORMATION STATEMENT...
Spotters are encouraged to report dense blowing dust.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Wind Advisory until 11 PM MST this evening for AZZ530.
CA...Wind Advisory until 11 PM PDT this evening for CAZ560>570.
Blowing Dust advisory until 11 PM this evening for CAZ563-566-
567.
&&
$$
DISCUSSION...Percha
PREVIOUS DISCUSSION...Hirsch/Rogers
AVIATION...Percha
FIRE WEATHER...AJ/Hirsch