Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/06/19
Area Forecast Discussion
National Weather Service Charleston SC
1013 PM EST Tue Nov 5 2019
.SYNOPSIS...
A cold front will pass through tonight. High pressure will
return Wednesday, before a stronger cold front crosses the area
Thursday night into Friday. High pressure will build in over
the weekend and prevail into early next week.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
As of 1010 PM: IR satellite showed a band of low clouds sliding
east across the Midlands, these clouds are likely associated
with the cold front. As the front approaches the forecast area,
cloud bases should lower below 1 kft. In addition, very low
values of sfc condensation pressure deficits indicate that fog
will develop along and ahead of the front. I will update the
forecast to add fog to the forecast through most of the night.
As of 825 PM: KCLX indicated that the inland showers have
largely dissipated over the past half hour. The rest of the
night should remain rain-free. It appears that low clouds and
possibly patchy fog will develop over the coastal areas late
tonight. I will update the forecast to reduce PoPs this evening
and increase cloud cover tonight.
As of 650 PM: KCLX detected a developing line of showers across
the inland counties of GA. CAMs indicate that these showers
will continue into the mid-evening hours and then dissipate. I
will update the forecast to adjust PoPs and Wx to the current
radar and model trends. Otherwise, the current forecast appears
on track.
Previous Discussion:
The coastal trough will slowly shift east farther off the coast
this evening. Meanwhile a cold front will sweep through from the
northwest later tonight. Although the strongest convergence
remains well offshore with the coastal trough, weak instability
has developed over land areas this afternoon and will support
isolated showers through early this evening. Temperatures will
not drop much lower than last night though some drier air will
begin working its way into the area late.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
Wednesday: Aloft, a zonal flow will prevail. At the sfc, high
pressure centered over the Mid-Atlantic states will wedge southward
Wednesday with north/northeast winds keeping all areas dry, but
slightly cooler than the previous day. In general, highs should
range in the low/mid 70s, warmest across Southeast Georgia.
Wednesday night lows should range around 50 well inland to mid/upper
50s closer to the coast.
Thursday and Friday: Aloft, a zonal flow will persist through much
of day Thursday before a large trough of low pressure digs over the
East Conus. At the sfc, high pressure will gradually weaken ahead of
a strong cold front advancing toward the area late. Expect winds to
slightly veer more onshore during the day and temps to warm a few
degrees higher with some warm air advection well ahead of the front.
A few models suggest some isentropic lift spawning showers Thursday
afternoon/evening, mainly across Southeast Georgia. However, the
bulk of precip activity is expected to arrive near the timing of the
cold front Thursday night into early Friday. PWATs peaking near 1.50-
1.75 inches along with weak instability suggest the bulk of precip
activity to be in the form of numerous to potentially widespread
showers along/ahead of the front. However, a few thunderstorms can
not be ruled out near the immediate coast, especially in Southeast
Georgia until fropa. Thursday night temps should remain mild with
clouds in place and fropa late. In general, lows should range in the
low-mid 50s away from the coast to around 60 degrees at the coast.
By daybreak Friday, the bulk of precip should be shifting offshore
as colder high pressure builds across the region. High temps will be
noticeably cooler Friday afternoon, generally ranging between the
low/mid 60s. By the evening, most areas should be dry, especially
away from the coast.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
A cool and dry fall weekend on tap. Models are in good agreement
that high pressure will dominate the surface weather pattern over
the weekend into early next week. Aloft, large scale troughing will
persist. Plenty of sun is expected with minimal rain chances. Late
in the period and beyond (Monday night into Tuesday), another strong
cold front is progged to cross the area. Temperatures will generally
be below normal, although will be moderating through the period. The
coolest nights of the season thus far are expected Friday and
Saturday night. We will need to watch for frost/freeze concerns.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
Prior to the 0Z TAFs, KCLX detected a developing line of showers
across the inland counties of GA. CAMs indicate that these
showers will continue into the mid-evening hours and then
dissipate. The primary concern for the 0Z TAFs will be the
placement, timing, and intensity of restrictive ceilings
tonight. MOS and forecast soundings indicate the IFR to LIFR
conditions will develop after midnight. In fact, HRRR sfc
condensation pressure deficits fall to around 1 mb after 5Z. I
will forecast MVFR ceilings between 4-5Z and will TEMPO a period
of at least IFR ceilings between 6-10Z. Building high pressure
should support steady NE winds by mid-day Wed.
Extended Aviation Outlook: Mainly VFR through the middle of the
week. There is a low chance for flight restrictions due to low cloud
ceilings Thursday. Greater chances for flight restrictions are
possible late Thursday through Friday due to showers along a passing
cold front. VFR conditions should return Saturday and persist
into Sunday.
&&
.MARINE...
Northerly winds will quickly increase after midnight following
the passage of the cold front. Some gusts to 25 kt are possible
in the Charleston nearshore and GA offshore waters closer to
daybreak Wednesday where we have Small Craft Advisories
beginning.
Wednesday through Sunday: High pressure will build across the waters
in wake of a cold front, leading to an enhanced pressure gradient
and higher winds/seas Wednesday. Small Craft Advisories will be
ongoing for northern South Carolina waters and offshore Georgia
waters through the day, before conditions gradually improve
Wednesday night. Winds/seas should then remain below Small Craft
Advisory levels for much of the day Thursday before a strong cold
front sweeps through the area Thursday night into early Friday.
Strong cold air advection behind the front will likely cause winds
and seas to deteriorate rapidly. Small Craft Advisories will likely
be needed for all coastal waters, but there is also a potential for
gale force wind gusts across some of the waters. Gale Watches and/or
Warnings could eventually be needed with peak conditions occurring
Friday night into Saturday, but conditions appear to fall just short
of Gale criteria. Winds/seas should then weaken/subside as high
pressure settles across the region Sunday.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...Small Craft Advisory from 4 AM Wednesday to 6 AM EST Thursday
for AMZ350-374.
&&
$$
NEAR TERM...NED
SHORT TERM...DPB
LONG TERM...ETM
AVIATION...NED
MARINE...DPB/JRL
Area Forecast Discussion
National Weather Service Duluth MN
957 PM CST Tue Nov 5 2019
.SHORT TERM...(This evening through Wednesday night)
Issued at 220 PM CST Tue Nov 5 2019
Unseasonably cold temperatures continue through Thursday with
high temperatures roughly where low temperatures should be this
time of year. A broad 500-mb trough sits over much of southern
canada and the northern United States, bringing cold air from
Canada down into the northern Plains with northwesterly flow.
Drier air will move in tonight as high pressure influences the
region, which will help to clear out some of the clouds for
northern parts of the area tonight. An area of low pressure will
pass through Iowa tonight with 500-hPa cyclonic vorticity
advection and 850-hPa warm air advection in southern minnesota
bringing an area of snow just to the south of our region tonight
into Wednesday morning. Most short-term guidance suggests snow
will stay well to the south of our region, but there`s a slight
chance that some light snow could affect our far southern borders.
The HRRR, NAM, and RAP models suggest there could be a little
light snow for southern portions of Price county Wednesday
morning, but impacts from this should be minimal. This system will
bring mostly cloudy to overcast skies to our region overnight,
especially along and south of Highway 2. Areas to the north should
stay partly cloudy. Low temperatures will reach the middle teens
tonight.
Winds will become northwesterly on Wednesday as a series of 500-mb
short waves move through, bringing in a reinforcing blast of cold
air from the north. There could be a few light snow showers
associated with this primarily during the late afternoon. The
biggest concern will be some lake effect snow showers developing
late Wednesday evening and overnight into Thursday morning
downwind of larger Minnesota lakes and along the South Shore of
Lake Superior with northwesterly winds. The NAM model even
suggests that bands off Lake Winnipeg may reach down into our CWA,
and with 850-mb temperatures as low as 17C, this seems possible.
Not anticipating any high amounts from this, but certainly a
coating to an inch is possible...maybe locally more if any bands
persist over the same area for several hours. Otherwise, high
pressure will move in with partly cloudy skies, at least for areas
not affected by lake effect. Low temperatures will hover around
10F, with some single digits possible as well.
.LONG TERM...(Thursday through Tuesday)
Issued at 220 PM CST Tue Nov 5 2019
Cold and mainly cloudy pattern through the long term forecast
period. After well below normal lows in the single digits above zero
on Thursday night, temperatures gradually trend warmer into Saturday
as a warm front approaches from the west. A cold front then move
from north to south on Saturday into Sunday leading to a chance for
light snow accumulations (less than an inch) and will begin an even
colder stretch of weather into early next week. Highs will be as
cold as the teens and lows in the single digits above zero to nearly
zero for some spots in northeast Minnesota.
On the synoptic scale a broad upper-level ridge over the west coast
will support additional intrusions of cold air from Canada across
the Midwest/Great Lakes through the next 7-10 days. This will cause
occasional low chances for light snow and below normal temperatures.
Late-week a broad area of high pressure will be centered over the
Upper Mississippi River Valley on Thursday, building east towards
the Ohio River Valley on Friday. This will lead to partly cloudy
skies Thursday clearing out Thursday night and causing lows in the
single digits to low teens. Clouds then increase on Friday as a
broad warm front approaches from the west leading to slightly warmer
temps, highs in the upper 20s to low 30s then as warm as the upper
20s to mid 30s on Saturday.
Late Saturday into Sunday a strong cold front approaches from the
north with 850mb temps as cold as -20C arriving by Sunday night
across the Northland, near record values per INL sounding
climatology and temperatures that would be considered well below
normal even in Jan/Feb. Any snowfall along and ahead of the cold
front Saturday will be light, up to an inch or so of snow possible
in most spots, except on the south shore of Lake Superior where the
snow belt region of northwest Wisconsin could see a few inches
Saturday night given the warm lake temperatures and very cold temps
aloft. Chances for light snow linger into the work week as there
remains a steady stream of low level moisture in the northwest flow
through Tuesday. Highs in the teens to near 20 Sun/Mon/Tues with
lows in the single digits above zero. Subzero temperatures are
possible north of the Iron Range each night. Skies remain partly to
mostly cloudy until Tuesday into Wednesday when a broad area of high
pressure and drier air builds in from the west.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 515 PM CST Tue Nov 5 2019
VFR through the TAF period as a system skirts by to our south.
Could see some shower activity Wednesday which may lead to sub-VFR
conditions, but for now have left out of TAFs due to low
confidence in development/timing.
&&
.MARINE...
Issued at 930 PM CST Tue Nov 5 2019
A system will pass through Iowa with largely high pressure over
Lake Superior and weak pressure gradients on the western side of
the lake. High pressure will build strongly Wednesday afternoon
increasing the pressure gradient and thus winds and waves too.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 13 27 13 23 / 10 10 0 0
INL 9 25 13 22 / 10 30 40 40
BRD 16 28 13 25 / 10 10 0 0
HYR 11 29 13 25 / 10 10 0 0
ASX 13 30 16 26 / 10 20 20 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...None.
&&
$$
SHORT TERM...JS
LONG TERM...JJM
AVIATION...Wolfe
MARINE...Wolfe
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
632 PM EST Tue Nov 5 2019
.AVIATION...
Diminishing downstream flux of moisture off lake Michigan combined
with the loss of daytime heating will leave simply a lower coverage
of VFR stratus going forward this evening - mainly across FNT/MBS. A
dry low level environment maintained by passing high pressure will
ensure quiet/VFR conditions persist overnight and Wednesday morning.
Moisture will increase along a frontal boundary expected to develop
across central lower MI Wednesday afternoon and evening. Greatest
impacts noted at MBS during the daylight period, with MVFR to IFR
conditions likely emerging within an increasing area of light
snowfall. FNT will witness a smaller window for similar restrictions
during the afternoon, while PTK and the Detroit corridor initially
reside outside the better moisture and favor prevailing VFR.
For DTW...Clear skies across lowest 5000 ft through Wednesday
morning. A lower ceiling will emerge with a limited window for
brief, light rain or snow showers Wednesday afternoon. Simply
highlighting this precipitation potential as prob30 - confidence in
occurrence remains quite low and the result inconsequential to
operations.
DTW THRESHOLD PROBABILITIES...
* Medium confidence for cigs to fall below 5000 ft Wednesday
afternoon.
* Very low confidence in the occurrence of a few light snow
showers Wednesday afternoon.
&&
.PREV DISCUSSION...
Issued at 400 PM EST Tue Nov 5 2019
DISCUSSION...
Dewpoints in the low to mid 20s with west winds today of 15 to 25
mph range has resulted in a wake-up call of sorts for the denizens
of Southeast Michigan. Conditions have been brisk with wind chills
running in the low to mid 30s. Relatively moist slab between 3.0 to
6.0 kft agl has supported overcast conditions with a flat
stratocumulus deck at the top of the mixed layer. Satellite trends
match up to model data suggesting that a subtle absolute vorticity
center is tracking across Lake Michigan this afternoon. Will likely
require this differential cva forcing to push across the area before
clouds scatter out rapidly. Maintained an optimistic cloud forecast
for tonight with mid-high moisture and clouds pushing into late.
Some question exists on how low temperatures will go tonight, but
with a mixed Given some mixed west flow, kept lows in the middle 30s.
A deep reservoir of high planetary potential vorticity is in place
over virtually all of northern North America this afternoon. Raob
analysis from this morning captured a strong +130 knot upper level
jet streak digging down the rearward face of the trough, impinging
down into the northern Plains. The jet axis is forecasted to pivot
to a zonal configuration by Wednesday morning. Interesting fact
about upcoming setup is the wavelength of the trough is so broad
that the typical subgeostrophic region to the trough base is non-
existent here locally. The rocking motion to the jetstreak is
expected to result in very strong and pervasive frontogenetic
forcing along the 850-600mb frontal zone that will be over the
northern CWA. Thus far, intra and inter model consistency has been
less than ideal which has brought a considerable amount of
uncertainty the Wednesday and Wednesday night precipitation forecast.
The main driver for the sensible weather forecast Wednesday the
magnitude of system relative isentropic ascent that will occur along
the 291-296k thetae surface beginning at roughly 18Z Wednesday and
continuing to around 09Z Thursday morning. The significant challenge
that exists with this forecast is predicting the amount of
lift/ascent that will occur along the sharp/upright midlevel frontal
boundary. This is not an easy call as latest 18Z NAM run is showing
more parallel system relative flow trajectories than the previous
12Z run. Just a remark on the lack of consistency. The big negative
is the lack of coherent deep thermal circulation riding along the
frontal boundary. The impressive aspect is the amount of system
moisture that will be available as upwards of 3.0 to 4.0 g/kg will
lift into far southern portions of the state by Wednesday afternoon.
Additional uncertain aspects of the forecast exist, notably... a
very dry antecedent airmass in the lowest 5000 ft agl and what the
efficiency of snow accumulations be with models adamant at surface
wet bulb temperatures reaching and exceeding the freezing mark. Do
respect the cold sounding and given the 12Z model trends for QPF -
long run of the RAP going at .40 liquid, did increase PoPs into the
high likely for snow with total accumulations Wednesday/Wednesday
night reaching 1.5 to 2.0 inches of snow. The failure point, and
could be a fairly dramatic one, is if system relative flow
trajectories are not orthogonal to the frontal slope that UVVs do
not develop.
Combination of sharp trough axis pushing directly into Southeast
Michigan and convoluted jet energy lifting through the cwa will
cause height rises and sharp cold front to push through the area at
the end of Wednesday night. Boundary layer cold advection will kick
in and result in a saturated/moist boundary layer at daybreak
Thursday. The near surface environment begins will above freezing at
10Z but crashes well below freezing after 12-13Z. Deep column theta
e will be shunted well to the south so no significant precipitation
during that time is anticipated. Rather will be looking at some
drizzle light rain showers trying to turn over to snow. Given the
above freezing temperatures not expecting any signficant impacts to
Thursday morning rush hour at Metro Detroit.
Very strong surface high pressure will build into the state for
Thursday and carry through the end of the week. Northwesterly flow
will limit any prospects for lake effect snow activity into
Southeast Michigan. The main narrative will be highs in the 30s with
wind chills in the teens and 20s.
Period of quiet weather is expected for Friday and Saturday as the
upper trough departs to the east and rebounding heights encourage
high pressure to build back into the Great Lakes and Ohio Valley.
Seasonably cool conditions will remain in place as 850mb temps in
the negative teens C will be slow to depart on Friday, but a slight
improvement will be seen for Saturday and Sunday. However, chance
for light snow increases by Sunday as an active polar jet streak
pushes in from the Canadian prairie. This jet will force a strong
cold front through by Sunday evening which brings the coldest air
mass of the season thus far with 850mb temps progged to reach about
-17C by late Monday. This pattern will keep a chance of snow showers
and temperatures well below normal values in the forecast through
the middle of next week.
MARINE...
Small Craft Advisories will be allowed to expire at 4 PM as winds
appear on track to drop below threshold values. High pressure builds
in tonight beneath a shallow ridge allowing for diminishing wave
action as winds become more benign. Winds back southwesterly on
Wednesday but speeds will be limited to the 10-15 knot range. A cold
frontal passage Wednesday night will bring about a wind shift to the
northwest prior to Thursday morning along with snow showers.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
Lake Huron...NONE.
Lake St Clair...NONE.
Michigan waters of Lake Erie...NONE.
&&
$$
AVIATION.....MR
DISCUSSION...CB/TF
MARINE.......KK
You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.
Area Forecast Discussion
National Weather Service Wichita KS
544 PM CST Tue Nov 5 2019
.SHORT TERM...(This evening through Thursday night)
Issued at 331 PM CST Tue Nov 5 2019
Quiet weather with near-normal temperatures were observed across
the area today. Across the Northern Plains, a front draped across
Montana, South Dakota, and Nebraska separates a much colder
airmass with temperatures in the 20s and low 30s to its north.
Closer to home, one important change to the forecast was the
addition of chances of drizzle or light rain overnight tonight in
southeast Kansas as increasing southerly flow and moisture
transport with isentropic upglide increases, particularly after
midnight. RAP forecast soundings depict this drizzle/light rain
potential as well. As a few of the previous discussions mentioned,
there remains some question about how much moisture will be
advected into the region and if it will actually be enough to
precipitate given the dry air above roughly 700mb in model
soundings, but trends support introducing at least some POPs
during the overnight/early morning hours.
Thinking a lull in precipitation during the day on Wednesday is
likely before more robust moisture makes its way into northern
Oklahoma and southern Kansas by late Wednesday afternoon into
Thursday. Agreement remains good that the focus of this system
will be in the Southern Plains, but at least some rain with
possible isolated thunder will be possible in south central and
southeast Kansas as well. Have continued low POPs in most of
central Kansas, but confidence further north in the forecast area
is lower. Though temperatures appear to be warm enough to make
rain the dominant precipitation type, as colder air is ushered in
overnight, a brief period of a wintry mix will be possible
Thursday morning. Overall, however, impacts should remain quite
low with little to no accumulations expected.
Northerly winds will increase behind the front as well overnight
Wednesday into Thursday as the tightened pressure gradient sinks
southward across the forecast area. Trended wind speeds upward
slightly with this issuance to favor the CONSMOS.
After complete departure of precipitation on Thursday, the main
highlight will be the much cooler temperatures on Thursday, with
afternoon highs reaching only into the low to mid-40s across the
area, which is well below normal for the time of year.
.LONG TERM...(Friday through Tuesday)
Issued at 331 PM CST Tue Nov 5 2019
During the day on Friday, a front will begin approaching central
Kansas, though, with very little moisture availability, things
should remain dry. There remain some differences in models for
this period regarding temperatures, with the ECMWF depicting more
downslope flow across Kansas and therefore warmer temperatures.
The GFS has been trending warmer on Friday as well, so in
collaboration with surrounding WFOs, bumped up Friday`s high
temperatures. Some of this southerly and downslope flow could
persist into Saturday as well, so bumped these up as well over the
NBM.
The warmer temperatures on Friday and Saturday could come to an
end as early as Sunday, however, as another trough and associated
surface front moves across the forecast area. The previous
forecasters have been consistently lowering high temperatures on
Sunday but with a wide range of model disagreement regarding the
timing of the cold front, there remains a lot of uncertainty with
how warm temperatures will get. Continued to trend on the lower
end of the model spread, but did not cool them as much as previous
forecasts given the uncertainty.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 534 PM CST Tue Nov 5 2019
Aviation concern will be low clouds moving into southeast KS late
tonight.
Surface high pressure is expected to slide east tonight into Wed
morning. As this occurs, south winds will allow moisture to creep
north into eastern OK and eastern KS. Confidence is high that IFR
ceilings will impact KCNU after 10z with some of these lower cigs
potentially making it as far west as KICT by around 12z. Some
drizzle will also be possible late tonight at KCNU.
The other story will be a strong cold front to move through Wed
afternoon through Wed evening, flipping winds around to the north.
Front will make it to KRSL around 19z and KICT closer to 00z Thu.
Some lower ceilings will be possible a few hours after the front
moves through as the colder air spills south.
&&
.FIRE WEATHER...
Issued at 331 PM CST Tue Nov 5 2019
Although red flag warning criteria and critical fire danger are
unlikely over the next several days, an influx of dry air on
Friday may produce very high grassland fire danger in a couple of
central Kansas counties. Otherwise, intermittent high grassland
fire danger is expected over the next week or so.
&&
.PRELIMINARY POINT TEMPS/POPS...
Wichita-KICT 43 65 31 43 / 10 40 70 10
Hutchinson 40 64 28 42 / 0 30 50 10
Newton 42 63 28 41 / 0 40 60 10
ElDorado 43 64 31 42 / 10 50 70 10
Winfield-KWLD 45 65 33 43 / 20 50 80 20
Russell 37 62 24 41 / 0 10 10 0
Great Bend 37 64 24 41 / 0 10 20 0
Salina 39 63 26 41 / 0 10 30 0
McPherson 39 64 26 41 / 0 30 40 10
Coffeyville 46 62 36 44 / 30 70 90 40
Chanute 43 62 33 43 / 20 60 80 20
Iola 43 62 33 42 / 20 60 80 20
Parsons-KPPF 45 62 35 43 / 30 70 90 30
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...TAV
LONG TERM...TAV
AVIATION...RBL
FIRE WEATHER...TAV
Area Forecast Discussion
National Weather Service Phoenix AZ
509 PM MST Tue Nov 5 2019
.UPDATE...Updated Aviation Discussion.
&&
.SYNOPSIS...
Above normal high temperatures with dry conditions are expected
through most of the week. The one exception will be very late
tonight and Wednesday when a weak weather system will bring slight
chances for isolated showers and thunderstorms mainly north and east
of Phoenix. High temperatures across the lower desert will be in the
mid to upper 80s, with lows in the mid 50s to lower 60s through next
weekend.
&&
.DISCUSSION...
Strong high pressure aloft is bringing another rather warm day (for
early November) across the region, with most lower desert locations
seeing temperatures well up in the 80`s at this hour, under mostly
clear skies. A weak low off the southern California and Baja coast,
easily discernible on water vapor imagery, is still expected to
provide a modest increase in moisture in the Southwest the next few
days. Surface dew points will increase from the current low 30s into
the upper 40s by Wednesday night while PWAT values also increase
close to 0.75 inches. That mark nears the 90th percentile for the
date according to the SPC sounding climatology.
Latest high-res model output continues to show the main upper low
lifting northeastward over extreme northern Baja tonight, then
across AZ on Wednesday. The combination of moisture and weak
dynamics is expected to produce isolated-scattered showers and
thunderstorms across the region very late tonight and on Wednesday.
Although the best chances for showers/TS will be over the higher
terrain north and east of Phoenix, a few showers cannot be ruled out
over SW AZ late tonight and over the lower deserts of south-central
AZ during the day on Wednesday as the cold core of the upper low
helps to destabilize the air mass, as depicted on the latest HRRR
runs. Although most of the SREF plumes do show a few hundreds of an
inch of rainfall for Phoenix, given the spotty nature of the
rainfall, it is likely that most locations will see no rain at all
(mainly just virga), with a few lucky spots receiving 0.10-0.20 of a
inch. The presence of these showers and an increase in cloudiness
should push highs down a bit across south-central AZ on Wednesday,
keeping them down in the mid-80`s. Modest instability (a couple of
hundred joules of CAPE) could also help to trigger an isolated
thunderstorm or two as well.
After the low moves eastward, the relatively persistent ridge will
restrengthen over the west coast. H5 height levels recover quickly
and rise through the weekend slightly above 580 dm. Combined with
generally sunny skies, temperatures will remain above seasonal
normal values near the mid 80s through the beginning of next week.
&&
.AVIATION...Updated at 0009Z.
South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
Limited aviation concerns expected over the next 24 hours with
winds remaining light and at times variable. An approaching
weather system will continue to support increasing mid and upper
level cloud coverage across south-central Arizona with broken cigs
aoa 10 kft developing around 10Z. Could see some virga Wednesday
morning while chances for a light shower increase late morning
into the early afternoon. Have added VCSH to all the TAFs, but
can`t completely rule out the possibility for an isolated
thunderstorm. However, the best chance for an isolated
thunderstorm will remain over areas north and east of Phoenix.
Cigs begin to scatter out tomorrow afternoon with scattered decks
remaining around 10 kft.
Southeast California/Southwest Arizona including KIPL and KBLH:
Few aviation concerns expected over the next 24 hours. An
approaching weather system will allow for an increase in mid and
upper level cloud cover with decks developing around 10 kft
overnight. Winds will remain light becoming variable at times
through the period.
Aviation Discussion not updated for amended TAFs.
&&
.FIRE WEATHER...
Friday through Tuesday:
Drier and warmer than normal conditions will be the rule over the
region on Thursday into early next week as the Desert Southwest
remains under the influence of high pressure or northwest flow
aloft. Minimum relative humidity values will stay above 20 percent
across south central Arizona on Friday before falling into the teens
for the weekend through early next week. Over southwest Arizona and
southeast California, relative humidity values will dip into the
teens each day with single digit values possible at some locations
early next week. Light diurnal winds should persist through the
forecast period.
&&
.SPOTTER INFORMATION STATEMENT...
Spotters should follow standard reporting procedures.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
DISCUSSION...Deems/Percha
AVIATION...Smith
FIRE WEATHER...CB/Percha
AREA FORECAST DISCUSSION
National Weather Service Raleigh NC
1001 PM EST Tue Nov 5 2019
.SYNOPSIS...
A dry cold front will move across the area tonight. High pressure
will settle into the Mid Atlantic on Wednesday before sliding east
off the DELMARVA Peninsula later Thursday. A stronger cold front
will slide east through the region Thursday night and Friday
morning, allowing even colder high pressure to fill into place.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 955 PM Tuesday...
A dry cold front will move across the area tonight. The bulk of the
cloud cover ahead of the front is shifting to the east of the area
this evening. The latest HRRR continues to show the potential for
some fog to developing this evening into the overnight ahead of the
front across the Coastal Plain of central NC (generally around the I-
95 corridor and to the east). Will need to monitor visbys, but do
not plan to issue a DFA at this time. The cold front should move
through eastern/southern portions of the area by around 5 AM or so,
ending any fog threat.
Low temps will be driven by CAA, with lows ranging from the lower
40s NW to the lower 50s SE.
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
As of 200 PM Tuesday...
By Wednesday, the CAA regiment will continue, with northerly to
northeasterly winds increasing to the 6 to 10kt range shortly after
sunrise. Mostly clear skies under high pressure should allow for a
typical diurnal temperature curve, only limited in magnitude by the
cP airmass features in place with plentiful surface subsidence.
Afternoon highs will settle in the low (north) to upper (south) 60s.
Overnight lows will be comparable to Wednesday morning temperatures,
bottoming out in the upper 30s to low 40s with good radiational
cooling conditions present.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
As of 150 PM Tuesday...
The 12Z NAM was not considered as heavily with the late week system
due to initialization errors and not receiving all 12Z upper air
balloon data.
An upper trough axis and surface cold front will approach the state
on Thursday. There is only a slight chance that rain showers will
receive the Triad before sunset, nearly all rain will occur
overnight. Still not impressed with the overall dynamics of the
storm, and have stuck with low likely pops on Thursday night. The
system does appear to be more progressive than it did yesterday, so
have decreased pops Friday morning across the east and eliminated
them for Friday afternoon. Colder air moving into the region may not
be as noticeable Thursday night, but certainly will be by Friday,
with many locations struggling to reach 50 degrees on Friday or
Saturday. Friday night should see all locations dropping below
freezing, with similar warmer temps Saturday night. High pressure
will move into the region Friday into Saturday, with a dry frontal
passage expected on Sunday considering there will be a lack of
moisture along the front. Monday and Monday night another upper
level trough will pass over the region. The GFS is much drier than
it was yesterday, with the ECMWF showing just a glancing blow of
precipitation. Have gone with just slight chance pops from Raleigh
to the north and east. While there will be some temperature recovery
Sunday and Monday, with most locations returning to the 60s, highs
will drop back into the 40s once again on Tuesday.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
As of 635 PM Tuesday...
24 hour TAF period: Fairly high confidence VFR conditions will
prevail through much of the TAF period, however there is a chance a
brief period of sub-VFR cigs/visbys could occur across eastern
terminals ahead of the front. Otherwise, just some scattered to
broken cigs around 4 kft are expected overnight at KRDU, KFAY and
KRWI. Winds will be calm to light and variable overnight, becoming a
bit strong in the east for a few hours in the morning/early
afternoon. -KC
Looking ahead: A cold front will approach the region late Thursday
and Friday providing the next chance of sub-VFR conditions,
primarily in the form of lowering CIGs/VSBYs associated with rain
showers. Cooler, drier, and quieter high pressure settles in for the
remainder of the weekend. -JJM
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...BSD/JJM
NEAR TERM...BSD
SHORT TERM...JJM
LONG TERM...Green
AVIATION...KC/JJM
Area Forecast Discussion
National Weather Service Topeka KS
537 PM CST Tue Nov 5 2019
...AVIATION UPDATE...
.SHORT TERM...(This evening through Wednesday night)
Issued at 308 PM CST Tue Nov 5 2019
Water vapor imagery at 1930Z shows an upper low situated over
Ontario with broad troughing across much of the northern CONUS
associated with this low. Extending from that feature, a weaker
circulation is noted approaching the Baja region of Mexico with a
ridge off the Pacific coast. Surface high pressure sits to our east
over the Upper Midwest while weak low pressure is developing in the
eastern Rockies.
We have some high clouds in northeast KS near the NE border, and we
should continue to see mostly clear skies and light winds this
evening and overnight as the surface high pushes east. WAA will
begin to develop overnight, which should keep lows a bit warmer in
the upper 30s to low 40s. In east central and southeast KS, we are
likely to see a surge of low-level moisture from the south, which
could bring some drizzle for a brief period early tomorrow
morning in the southeastern CWA. Depending how much moisture moves
in and how widespread it becomes, could see some patchy fog or
low stratus as well, but at this time have just brought in slight
chance PoPs southeast of I-35 to account for drizzle.
Heading into Wednesday morning, a cold front approaches the KS/NE
border and we`ll continue to see WAA ahead of the boundary before it
pushes south through the afternoon and evening. The surface front
should be entirely south of the CWA by midnight Thursday while the
850mb front will take a bit longer, likely not getting south of the
area until early Thursday morning. The overall best forcing and
highest chances of precip look to be trending south of our area, and
moisture isn`t overly impressive Wednesday evening into early
Thursday. East central KS has the best chance of seeing anything,
and NAM forecast soundings best support drizzle as temperature
profiles stay mostly above freezing. It`s worth noting there is a
cold layer in the low levels that gets below freezing after
midnight, but surface temps remain above freezing. Saturation only
occurs from 800-925mb and we already show signs of drying as we get
closer to sunrise. That being said, thinking drizzle is the most
likely precip type with only a very small opportunity to see any
freezing drizzle if we cool to the wet-bulb temperature. RAP
soundings stay above freezing through the entire period, which
further supports the theory for drizzle. Highs Wednesday will reach
the low to mid 60s ahead of the front, cooler in the 50s near the
KS/NE border, with lows falling back to the mid 20s to low 30s
Wednesday night.
.LONG TERM...(Thursday through Tuesday)
Issued at 308 PM CST Tue Nov 5 2019
Transitioning into the extended period, any lingering drizzle and/or
snow flurries will come to an end early Thursday morning across east-
central KS. Otherwise, surface ridging will build into the area
through the Thursday, yielding mostly sunny skies and light winds
for the area. The light winds and clear skies will set the stage for
a cold morning Friday with lows in the lower 20s. A weak cold will
approach the area Friday into Friday night as a weak midlevel
shortwave trough translates through the northwest flow. Little in
the way of CAA is anticipated given the weak nature of the midlevel
shortwave. A nice warmup is expected for Saturday, ahead of the next
cold front, as southwesterly to westerly winds usher in warmer
temperatures. Afternoon highs Saturday are expected to reach the low
to perhaps middle 60s. The aforementioned secondary cold front will
push through the CWA late Saturday night into early Sunday. As a
result, much cooler temperatures are expected for Sunday with
daytime highs in the 40s. Continued CAA into Sunday night and Monday
will result in well-below normal temperatures with lows in the
10s/20s and highs in the 30s. &&
.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1134 AM CST Tue Nov 5 2019
Light SE winds will continue this afternoon/evening with mostly
clear skies. By tomorrow morning, models hint at a surge of
moisture from SE KS potentially bringing in fog or low stratus,
but confidence remains low on this reaching TOP/FOE. Could see
MVFR/IFR cigs or vsby if this occurs, otherwise VFR conditions
should continue for the period.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday)
Issued at 537 PM CST Tue Nov 5 2019
There is good agreement among the models in a slug of low level
moisture advecting into east central KS by Wed morning. The main
uncertainty is how far north this moisture may get. With the
RAP/NAM/GFS forecast soundings saturating low levels at TOP and
FOE for a few hours, have introduced some MVFR CIGS. Although the
moisture advection could be low enough that the stratus comes in
below 1000 FT. Confidence is only about average as much of the
objective guidance keeps the CIGS just to the southeast of TOP and
FOE. It may not be out of the question that an advection fog
develops given dewpoints in the lower and mid 40s are progged to
move north overnight. So will monitor trends and adjust
accordingly. Thanks for the coordination EAX.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Picha
LONG TERM...Baerg
AVIATION...Wolters