Special Briefings

TK’s Special Briefing….

by troyk | on Dec 10, 2013 | Comments Off

This is where I will post special updates during periods of severe and/or inclement weather.

TK’s Special Briefing….

by troyk | on Dec 07, 2013 | Comments Off

Austin / Travis County and South Central Texas Weather Update #8 – FINAL UPDATE
Prepared by Incident Meteorologist Troy Kimmel (www.troykimmelweather.com)
1200pm CT – Saturday / 7 December 2013

.. Weather Update # 8 ..

There are NO current NWS watches/advisories/warnings for counties in our immediate
area from the following NWS offices…

NWS/Austin-San Antonio…
NWS/Fort Worth…

DISCUSSION

…. Very Slim Precipitation Chances Today ….
…. Freezing Temperatures Continue ….

With arctic air entrenched over the area.. a weak upper air disturbance, today into early tonight,
may trigger a few flurries, maybe a little sleet or even some light freezing drizzle. Even so, the
probability of precipitation is less than 20% for any given location in our forecast area.

In short, I do not anticipate any problems.. although I’ll continue to monitor in case the situation
changes.

Temperatures are not expected to go above freezing until mid and late morning tomorrow (Sunday)
with a hard freeze is most areas tonight ranging from the lower 20s in the hill country areas to the
west to the mid 20s along and east of the IH35 corridor.

This will be my last email statement as it regards this specific event.

Bundle up and have a good, safe and warm weekend..
tk

TK’s Special Briefing….

by troyk | on Dec 06, 2013 | Comments Off

Austin / Travis County and South Central Texas Weather Update #7
Prepared by Incident Meteorologist Troy Kimmel (www.troykimmelweather.com)
430pm CT – Friday / 6  December 2013

.. Weather Update #7 ..

… Good News …
There are NO current NWS watches/advisories/warnings for counties in our immediate
area from the following NWS offices…

NWS/Austin-San Antonio…
NWS/Fort Worth…

It is possible that new NWS issuances may be necessary by late tomorrow through
tomorrow night into early Sunday. I will continue.. as will the NWS/Austin-San Antonio
office.. to keep you advised reference this possibility.

DISCUSSION

…. Our First Upper Air Disturbance has Passed …
…. Another Weak Disturbance Due Tomorrow Night into Early Sunday …
…. Perhaps Other Passing Disturbances Again Early Next Week ….

Assisted by a massive area of counterclockwise rotating upper air low pressure over southern Canada
and the western USA.. the unseasonably cold arctic surface air mass continues to slide southward out of
Canada into the western two thirds of the USA. The heart of this arctic air is still centered over northern
Alberta (Canada) with mid day temperatures today under a surface high pressure area- north of Edmonton –
as cold as -31 degrees F. As this cold  air continues to surge south southeastward into the southern plains,
it is still in a relative shallow layer close to the ground over our area. This is combining with an active
subtropical jet stream.. from the Pacific Ocean to our southwest… to cause moisture to overrun the cold air
overhead. In that upper air flow, weak northeastward moving upper air disturbances are expected to move
overhead between now and Sunday and perhaps even early next week, create lift in the atmosphere and, as
a result, cause precipitation at times.

With the unseasonably cold arctic surface air in place outside, the first of those disturbances passed over our
area last night into this morning with the dangerous icy conditions on bridges and overpasses in the northern
and western Austin metro area and the northern part of the IH35 corridor. With that system having passed off
to the northeast now, there is no longer precipitation across the area. In fact, we’ve actually seen some breaks
in the overcast in some areas this afternoon in the wake of the disturbance. However, clouds will continue, for
the most part, to hold in through the weekend.

We’ll continue this precipitation lull until midday and early afternoon tomorrow. After about 3pm tomorrow and
continuing through tomorrow night and into Sunday morning, another weak upper air low pressure disturbance
traverses the area southwest to northeast. With additional cold surface air advecting into the area.. I expect
that we will see freezing temperatures tonight with temperatures struggling to get to near freezing tomorrow.
Temperatures will then fall to well below freezing areawide tomorrow night. Even with lower precipitation
probabilities (around 30% for the Austin area) as the next disturbance passes, we must still consider that even
a light freezing rain or drizzle could cause problems especially on bridges and overpasses tomorrow night into
early Sunday. At this point, guidance suggests that rainfall equivalents for tomorrow night should be somewhere
in the trace to 0.10″ range.. with ice accumulations expected to be light but still potentially a factor. Precipitation
from this disturbance should shut off by midday Sunday as the disturbances passes to our northeast.

By late in the weekend and into next week,  numerical computer and manual forecast guidance is now suggesting
that we might deal again with the possibility of freezing/frozen precipitation.. although with slim chances.. Sunday
night into Monday morning and again, perhaps, Monday night into Tuesday. Sorry to bring you this news, but I’d
rather you be aware and proactive rather than us having to be reactive. >From my standpoint, I’ll “fight one battle
at a time”.. and I’ll do my best to keep you informed from one event to potentially another (anyone care to take a
guess how high my weather update numbers – in the reference line – will become before the end of next week????).

As mentioned in earlier updates, this cold arctic air will continue to be reinforced from the north through the
weekend and into next week. The surface air is dense and heavy will be hard to dislodge. Based on the guidance
I’m seeing now, I would be surprised if we’re back above 50 degrees F for high temperatures until about next
Thursday or Friday.


I’ll continue to monitor this situation.

Bundle up and have a good, safe and warm weekend..
tk

TK’s Special Briefing….

by troyk | on Dec 06, 2013 | Comments Off

Austin / Travis County and South Central Texas Weather Update #4
Prepared by Incident Meteorologist Troy Kimmel (www.troykimmelweather.com)
700am CT – Friday / 6  December 2013

.. Weather Update #4 ..

NWS watches/advisories/warnings that have been issued and updated as of 700am CT:

NWS/Austin-San Antonio… a WINTER WEATHER ADVISORY continues for the Texas
Hill Country and IH35 corridor.. including Williamson, Travis, Hays, Bastrop, Caldwell and
Lee Counties.. until 2 pm today for possible ice accumulations to less than 1/10th of an inch.

NWS/San Angelo… a WINTER STORM WARNING continues for Mason County
from now until 12 noon today for possible ice/sleet accumulations of up to 1/4 inch.

NWS/Fort Worth… a WINTER STORM WARNING continues  until 6pm today for large areas
of north Texas.. including the DFW area.. for the likelihood of significant 1/4 to 1/2 inch or more
ice/sleet accumulations with downed trees and power lines possible with power outages already
being reported.
A WINTER WEATHER ADVISORY continues until 6pm today for the area to the
southeast of the warning area above and to including Bell, McLennan and Milam counties..
including the Killeen.. Belton.. Temple.. Waco and Cameron/Rockdale areas for the possibility
of ice/sleet accumulations of up to 1/10th inch.

DISCUSSION

…. Icing Bridges/Overpass Problems Immediate North through West of Austin Area …

The unseasonably cold arctic air mass continues to slide southward out of Canada into the through the
western two thirds of the USA. As this cold air continues to move southeastward through Texas, it, as
usual, is in a relative shallow layer close to the ground. This is combining with an active subtropical
jet stream to cause moisture to overrun the cold air and then upper air disturbances embedded in the
subtropical jet stream to move by between now and Sunday, create lift in the atmosphere and, as a result,
cause precipitation at times.

An upper level low pressure disturbance has increased lift in the overrunning moisture above the surface
based cold air with light freezing rain and rain in the overnight hours. Freezing temperatures or below
are noted northwest of a line from near Wimberley /Hays County/ northward through the western and
northern parts of the Austin metro area.. then eastward through Pflugerville and then into extreme
southeastern Williamson County to near Thrall.. Thorndale and Rockdale in Milam County.
Radar indicates only patchy precipitation in the area currently but overnight rains have resulted in
some dangerous icing on elevated toll road bridges and overpasses in northwest Austin and into the
Round Rock area.

As the current upper air disturbance moves east northeast of the area by midday today.. precipitation
will taper off and the current winter precipitation threat will diminish.

This arctic cold air will hang in here for the next week or so with another winter weather risk existing for the
local area for Saturday into Saturday night and  into early Sunday morning time period as another upper air
low pressure disturbance moves by.. these time periods will be dealt with by the NWS with possible later
watches/advisories/warnings
.

A continued reminder to let you know.. as predicted.. of the widespread and dangerous winter weather and
ice storm situation that has developed well  to our north over north Texas, Oklahoma into adjoining
Arkansas where WINTER STORM and ICE STORM WARNINGS continue. Widespread power outages
have already been reported in north and far northeast Texas.. including the Dallas/Fort Worth metroplex.

Another note… this cold arctic air will continue to be reinforced from the north through the weekend and
into next week. Based on the guidance I’m seeing now, I would be surprised if we’re back above
50 degrees F for high temperatures until about 6 days from now. More importantly, overnight lows
next week, assuming a clearing sky, will result in hard freezes in the overnight areas with some areas to
around 20 degrees F for overnight lows on Monday/Tuesday/Wednesday nights of next week. The good news..
at this time.. is that no precipitation is expected for this time period.


I’ll continue to monitor this situation.

tk

TK’s Special Briefing….

by troyk | on Dec 05, 2013 | Comments Off

Austin / Travis County and South Central Texas Weather Update #3
Prepared by Incident Meteorologist Troy Kimmel (www.troykimmelweather.com)
500pm CDT – Thursday / 5  December 2013

.. Weather Update #3 ..

NWS watches/advisories/warnings that have been issued and updated as of 500pm CT:

NWS/Austin-San Antonio… a WINTER WEATHER ADVISORY will be in effect for the Texas
Hill Country and IH35 corridor.. including Williamson, Travis, Hays, Bastrop, Caldwell and
Lee Counties.. from 8pm tonight through 2 pm Friday for possible ice accumulations to 1/10th
of an inch by tomorrow morning.

NWS/San Angelo… a WINTER STORM WARNING is now in effect for Mason County
from now until 12 noon Friday for possible ice/sleet accumulations of up to 1/4 inch.

NWS/Fort Worth… a WINTER STORM WARNING is or will shortly be in effect until
6pm Friday for areas northwest of a line from Goldthwaite to Canton line for the likelihood
of significant 1/4 to 1/2 inch ice/sleet accumulations with downed trees and power lines possible
with lengthy power outages possible.
A WINTER WEATHER ADVISORY will be in effect 6am Friday until 6pm Friday for the area
southeast of the warning above and to include Bell and McLennan counties.. including
the Killeen.. Belton.. Temple and Waco areas for the possibility of ice/sleet accumulations of
up to 1/10th inch.

DISCUSSION

…. Increasing Likelihood of Freezing Rain Overnight ….

The unseasonably cold arctic air mass continues to slide southward out of Canada into the through the
western two thirds of the USA. As this cold air continues to move southeastward through Texas, it, as
usual, is in a relative shallow layer close to the ground. This is combining with an active subtropical
jet stream to cause moisture to overrun the cold air and then upper air disturbances embedded in the
subtropical jet stream to move by between now and Sunday, create lift in the atmosphere and, as a result,
cause precipitation.

The front arrived in the Austin area about 4 to 5am this morning with rain showers and light rain along
and just behind the front. Although we haven’t seen any precipitation today, clouds have held temperatures
in the upper 30s to near 40 all day long.

By later tonight, the leading edge of a low pressure disturbance will begin to increase lift in the overrunning
moisture above the surface based cold air with light rain beginning.. with temperatures just above freezing..
later tonight. After midnight tonight, our surface temperatures will approach the freezing mark and
precipitation will transition to freezing rain with ice accumulations beginning to form on higher bridges
and overpasses as well as exposed objects. As this rain falls into the early morning hours tomorrow, please
understand that if temperatures remain a degree or two warmer that we’re expecting, this will be a simple
cold rain event locally. On the other hand, if temperatures fall several degrees lower than anticipated, we could
rapidly find ourselves in a full winter storm situation. I would love to be able to tell you which of these
scenarios will play out… but I can’t at this point as there is just too much uncertainty. The NWS Austin-
San Antonio has mentioned that it is possible that the winter weather advisory may have to be upgraded to
a winter storm warning over parts of our area later tonight into Friday but it’s just simply too soon to tell.
This means that this may be more “last minute” as whether we have ice accumulations locally from
this system.. we’ll need to watch the 12 midnight to 7am period overnight tonight to get a real idea about this
winter storm and whether it will directly affect our area.

This arctic cold air will hang in here for the next week or so with another winter weather risk existing for the
local area for Saturday into Saturday night and  into early Sunday morning time period as another upper air
low pressure disturbance moves by.. these time periods will be dealt with by the NWS with possible later
watches/advisories/warnings.

A continued reminder to let you know of the potentially widespread and dangerous winter weather (ice storm)
situation that map develop to our north over north Texas, Oklahoma into adjoining Arkansas where
WINTER STORM and ICE STORM WARNINGS are already in effect. This could cause widespread
and long lasting power outages in north and northeast Texas.. including the Dallas/Fort Worth metroplex
as well as the Longview/Tyler/Kilgore as well as Texarkana areas over the coming days.

Another note… this cold arctic air will continue to be reinforced from the north through the weekend and
into next week. Based on the guidance I’m seeing now, I would be surprised if we’re back above
50 degrees F for high temperatures until about 7 or 8 days from now. More importantly, overnight lows
next week, assuming a clearing sky, will result in hard freezes in the overnight areas with some areas to
around 20 degrees F for overnight lows on Monday/Tuesday/Wednesday nights of next week. The good news..
at this time.. is that no precipitation is expected for this time period.


In conclusion, even as the winter storm is already directly affecting other parts of the state, there is still much
uncertainty
about this potential winter weather event locally for our south central Texas area tonight into
tomorrow. On the other hand, please understand and appreciate the very high impact that this system could
have on our area with very little notice if temperatures turn out being even slightly colder over our area than
we’re currently forecasting now. It is so very important that all interests pay close attention to the latest
weather conditions over the coming days and for the latest NWS watches/advisories and/or warnings that may be
issued.

I’ll continue to monitor this situation.

tk