FEBRUARY 2018 - Roller Coaster WX To End February

[Katdaddy]

Temps in the low to mid 40s across SE TX and the Upper TX Coast with some 30s across inland areas. Many areas will see some partly cloudy skies today. Enjoy the sun if you see it today because more clouds arrive tonight with a slight chance of showers across W and SW portions of SE TX later tonight. Clouds and rain chances will remain through the weekend and into next week as the active weather pattern continues onward but we may see some low 70s for Saturday.

[unome]

clear skies here - cool little cloud pyramid sliding SW on GOES-16

http://rammb-slider.cira.colostate.edu/ ... mmb-slider

https://weather.msfc.nasa.gov/cgi-bin/b ... _drop=show

[srainhoutx]

Canadian has wintry mix action around the Hill Country Sunday - Monday. Euro running pretty cold then. Another cold surge possible around the 20th. Early this morning to sink towards the freezing point in CLL and northern counties.

The NAM and the SREF also suggest in their longer range that freezing rain/ mixed with some sleet may be possible Sunday. We might need to follow those trends a little closer tomorrow as the freezing line creeps closer to our Northern Areas Sunday afternoon.

[tireman4]

Drier Conditions Today...

[tireman4]

000
FXUS64 KHGX 081155
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
555 AM CST Thu Feb 8 2018

.AVIATION [12Z TAF Issuance]...

Night time microphysics imagery and fog imagery from GOES East
has been very helpful finding where clouds are clearing from NE to
SW. MVFR ceilings early this morning have slowly eroded with the
clearing line now from Columbus to Pearland. This leaves KLBX and
KGLS yet to clear out but based on guidance, the clearing line may
stall along the coast. TAFs for KLBX and KGLS have some clearing
but then MVFR decks back by the afternoon. The rest of the TAFs
remain VFR until the evening hours. Isentropic lift increases
overnight allowing for ceilings to decrease with a few -SHRA/-RA
possible through 12Z Friday. Ceilings may begin to decrease into
IFR levels 10-15Z Friday and hinted at that with tempo groups. GFS
guidance may be too aggressive with this while SREF probabilities
show little only some low end probabilities of IFR just along the
coast. Friday night into Saturday looks like a better period for
IFR conditions.

Overpeck

&&

.PREV DISCUSSION /Issued 428 AM CST Thu Feb 8 2018/...

.SHORT TERM [Today Through Sunday]...
As of 3 AM this morning, temperatures have continued to fall into
the low 30s to mid 40s across much of the region. Skies are beginning
to clear in our northern counties this morning, as dry air filters
into the region with a surface ridge building in from the north.
Partly cloudy skies remain in place due to a lower layer stratus
deck for much of the area south of I-10, while high clouds stream
overhead across much of SE TX.

Early Friday morning, high pressure will shift east, and a warm
air advection pattern takes hold Thursday into Friday. Moisture
begins to creep back into the region as winds turn easterly by
Friday morning. Short term guidance such as the HRRR and RAP13
are hinting at the potential for a shower or two possible west of
I-45 early Friday morning. This return flow will bring a substantial
increase in precipitable water values (PWs) and with southwesterly
flow along aiding in isentropic lift, widely scattered showers
will be possible late Friday morning and into the afternoon
hours. PWs will rise nearly an inch across portions of the region,
from Thursday into Friday afternoon, eventually reaching 1.5-1.65
inches. As a result, dew points rise back into the low 60s south
of I-10 with upper 50s to the north by Friday afternoon. Better
chance for overall coverage can be expected Friday evening into
Saturday morning, as a coastal trough transitions into a warm
front which will then advance north through the Gulf waters. This
feature should shift over the coastal counties and move further
inland through the early morning hours Saturday, dragging with it
a fairly saturated airmass.

Friday evening into Saturday morning, the chance for sea fog
returns as dewpoints again rise into the low to mid 60s. Winds
will be out of the southeast and the potential for some patchy sea
fog will be possible over the bays and nearshore waters. This sea
fog could shift inland and impact the coastal counties, potentially
lowering visibilities through much of the day Saturday until this
weekend`s cold front is able to push off the coast. The SREF has
indicate this potential for patchy fog development over much of
the region Saturday. Have gone ahead and added patchy fog into
the forecast starting Friday evening and carrying through much of
the day Saturday, especially along the coast.

A section of the subtropical jet stream works its way over the
region beginning early Saturday morning and places Southeast
Texas in a left exit region of a 90 kt jet streak at 250 mb late
Saturday into Sunday. Additionally, the timing of this weekend`s
cold front has sped up moving the front through late Saturday into
early Sunday. The NAM is the fastest of the global models, with
the Canadian not far behind, pushing the front off the coast by
sunrise Sunday morning. The ECMWF pushes the front off the coast a
tad later by mid Sunday morning while the GFS remains the slowest
model moving the front through the region by late Sunday morning.
Therefore, the best chance for showers and thunderstorms with this
system will be late Saturday into Sunday morning.

At this time have leaned towards a blend of the ECMWF and NAM, as
the ECMWF has consistently been faster with the front, in addition
to the NAM hoping on board with the faster solution. Therefore,
have taken a colder approach for the temperatures Sunday and
Monday with highs in the mid 40s-50s and lows in mid 30s to 40s.

Hathaway


.LONG TERM [Monday Through Thursday]...
Lower PoPs in play for Monday, as another region of high pressure
attempts to slide into the region. Temperatures will also be on
the rise through the middle of next week, with high temperatures
reaching into the upper 60s to lower 70s Tuesday and Wednesday.

In the far extended, global models are picking up on potentially
another upper level disturbance working its way into SE TX
Wednesday into Thursday. The GFS forecast soundings are indicating
the potential for PWs to rise back above 1.5 inches by Wednesday
evening. At this time, keeping a chance of showers and isolated
thunderstorms in the forecast for the late Wednesday time frame
and carrying showers over into early Thursday.

Hathaway

.MARINE...
North to northeast winds should continue to decrease this morning in
the offshore waters of the Upper Texas Coast. The advisory was
extended until 12Z/6AM since borderline advisory conditions are
observed just before the previous expiration time. Caution
conditions should last through the morning with winds dropping below
15 knots by 18Z today. Decreasing winds should allow for seas to
gradually subside.

Forecast models are in pretty good agreement with onshore winds
developing Friday into the weekend. Sea fog may be possible again
Friday night into Saturday as dewpoints rise back into the upper 50s
to low 60s. Fog will be possible through Saturday night. Forecast
models are becoming more aligned as to when the next cold front
pushes off the coast. NAM/Canadian/ECMWF all faster with the front
than the GFS so leaned on a blend of those models for frontal
timing. This has the front off the coast 12-18Z Sunday so fog could
possibly persist until Sunday morning. Winds should be strong enough
behind the front to need caution or advisories issued for late
Sunday. Winds decrease and turn to the northeast on Monday.

Overpeck

&&

.PRELIMINARY POINT TEMPS/POPS...

College Station (CLL) 58 47 67 56 69 / 10 20 30 40 30
Houston (IAH) 56 49 66 58 71 / 10 20 40 60 50
Galveston (GLS) 54 53 63 58 68 / 20 30 40 60 50

&&

.HGX WATCHES/WARNINGS/ADVISORIES...

TX...None.
GM...Small Craft Advisory until 6 AM CST early this morning for the
following zones: Coastal waters from Freeport to the
Matagorda Ship Channel out 20 NM...Coastal waters from High
Island to Freeport out 20 NM...Waters from Freeport to the
Matagorda Ship Channel from 20 to 60 NM...Waters from High
Island to Freeport from 20 to 60 NM.

SMALL CRAFT SHOULD EXERCISE CAUTION until noon CST today for the
following zones: Coastal waters from Freeport to the
Matagorda Ship Channel out 20 NM...Coastal waters from High
Island to Freeport out 20 NM...Waters from Freeport to the
Matagorda Ship Channel from 20 to 60 NM...Waters from High
Island to Freeport from 20 to 60 NM.


&&

$$

NEAR TERM...08
SHORT TERM...08
LONG TERM...08
AVIATION...Overpeck
MARINE...Overpeck

[DoctorMu]

Reports from our northern counties have noted that a strange, bright yellow orb has been highly visible in the eastern sky this morning. El Sol, many of the locals call this unusual meteorological event. A phenomenon that can suddenly appear, then disappear for long periods this time of the year, with a noisy southern jet.

.

[tireman4]

I believe that this object is partially to blame...

[srainhoutx]

Clouds have moved back North into SE Texas and it appears we have a very active, wet and changeable forecast ahead into next week. I see almost daily chances of some precipitation through at least the next 7 days with little if any sunshine with a very noisy sub tropical jet overhead.

The Updated CPC Day 8-14 Extended Outlook has some significant changes across the Central United States that likely will change day to day as the various computer schemes attempt to resolve the Polar Vortex Split and Sudden Stratospheric Warming Event early next week. This is a highly volatile pattern with a lot of uncertainty. So expected changes throughout the month as we near the end of February.

[mckinne63]

Off topic: What did they do to the KHOU site? I neglected to bookmark this page, just would come here thru the main site by clicking on weather and than forums. The forum is nowhere to be found on the new site. Luckily I found an old email so I got here. The new KHOU site is not so good and not good for this forum. I know everyone that is here will always be here, but how are newbies going to find this forum?

[srainhoutx]

The WPC issues Marginal Risk for Excessive Rainfall across portions of SE Texas.

[unome]

this works for me http://lmgtfy.com/?q=khou+weather+forum but you are right, a search on their updated site did not find the forum for me, either I do like their new site layout, though.

Off topic: What did they do to the KHOU site? I neglected to bookmark this page, just would come here thru the main site by clicking on weather and than forums. The forum is nowhere to be found on the new site. Luckily I found an old email so I got here. The new KHOU site is not so good and not good for this forum. I know everyone that is here will always be here, but how are newbies going to find this forum?

[srainhoutx]

My suggestion is email web@khou.com and express your views regarding the change. Now my 83 year old Mom and her friends will be lost..

[srainhoutx]

Friday morning briefing from Jeff:

Heavy rainfall possible late tonight and Saturday.

Main threat at this time appears to be street flooding, but rapid rises on area creeks and bayous also possible.

Short term meso scale models have trended toward a higher risk of training heavy rainfall over SE TX early Saturday morning. Ingredients will come together late tonight and early Saturday for a round of showers and thunderstorms. A coastal warm front will push inland toward the US 59 corridor while moisture levels increase along and ahead of this boundary. Additionally a strong sub-tropical jet streak overhead will help to lift the nearly saturated air mass. We have been schooled several times in this area with slow moving boundaries, especially warm fronts and the overall setup favors heavy rainfall production.

With PWS increasing to near 1.5 inches expect rainfall rates to potentially reach 2 inches per hour in the heavier rainfall cores. Overall concern is the threat for sustained cell training along the warm frontal boundary that may last a few hours. On average storm totals of 1-3 inches with isolated amounts possibly up to 4 inches. While these totals are not typically excessive for this area, the time of year, lack of evaporation recently, and nearly completely dead vegetation all result in higher run-off rates.

Main threat will likely be street flooding where short term rainfall rates overwhelm local street drainage capabilities. While rises on area bayous and creeks are likely, significant overbank flooding is not currently expected.

[stormlover]

will tomorrow be a all day affair? what time frame we looking at?

[don]

The national weather service even mentions the possibility of issuing a flash flood watch.

.SHORT TERM [Tonight Through Sunday]...

The best way to describe the forecast tonight into Saturday is to
say "Well that escalated quickly." The last few days the models
had been pushing a lot of the heavy rainfall into east Texas and
Louisiana leaving SE Texas with a decent chance at rain but not
quite the heavy rainfall. That seems to be changing with the
latest hi-res mesoscale models and event some of the synoptic
models. As for the synoptic models, the NAM/ECMWF/Canadian all
have similar timing with rainfall starting around 06Z Saturday and
going through 18Z Saturday or even 00Z Sunday. The GFS starts
precip earlier around 03Z Saturday and quickly moves heavy
precipitation NE by 12-15Z Saturday. As for the mesocale models,
the WRF-ARW and Texas TX WRF hit the area with heavy rainfall in
the 06Z to 18Z Saturday time frame. SPC HREF shows about 3 or 4 of
the 8 members with heavy rainfall during a similar period. There
seems to be growing confidence in the potential for heavy
rainfall. WPC has a marginal risk of excessive rainfall for the
area also noting that over-performing convection could be
possible for the early morning hours Saturday.

From a pattern recognition standpoint, there is a pretty good
subtropical jet streak that will move over the area Friday night
through Saturday putting divergence over the region with the left
exit region of the jet. Warm air advection is on going and models
show precipitable water values around 1.5 to 1.7 inches across the
area by 12Z Saturday. These values are in the 99-99.5 percentile
for the 30 year CFSR climatology. So with that much moisture and
that much large scale lift, there should be thunderstorm activity
that develops and organized. Let`s also add a 30 knots LLJ off the
Gulf and 20 knots of 0-1km shear and you get a very favorable
environment for heavy rainfall. Forecast has been updated for
higher rain chances and higher amounts of QPF.

Right now the forecast has the heavy rainfall threat basically
south of a Livingston to Tomball to Edna TX line which includes
the Houston metro area. Rainfall amounts will likely average 1 to
3 inches through Sunday morning. Areas to the north of that line
may get a half inch to an inch of rainfall. The problem will be
storms that are capable of producing 1-2 inches of rain in an hour
which could lead to flooding problems especially in urban areas.
Isolated areas of 4 inches could be possible which will be close
to if not exceeding flash flood guidance in a few areas. In the
urban areas, that much rainfall will cause rapid increases in the
bayous and street flooding in the usual low lying areas. Since
these model trends are fairly new, we will hold off on a flash
flood watch but this will be closely monitored during the day.

After this threat of heavy rainfall moves east, a cold front will
push through the area Sunday and drop temperatures during the day.
Temperatures Saturday night will start in the 50s and 60s and
reach the low 40s Sunday evening. There will still be a chance of
rain but not the heavy rainfall threat.

http://forecast.weather.gov/product.php ... glossary=1

[srainhoutx]

I have been advised by KHOU Web Director that the Weather Forum link on KHOU.com will be re established as soon as possible. Their new site is still being attended to by the developer and a request has been sent to restore the Weather Forum link today, if possible.

[stormlover]

srain can we get an updated about the weather tomorrow with the new model runs?

[jasons2k]

I'm just glad it's warm enough to venture outdoors again. Pleasant lunchtime walk on the Waterway to grab some lunch. Looks like baseball practice tomorrow will be rained-out, but I'm not complaining. I'll take all the rain we can get before the summer death ridge. I hope this spring we are not plagued by a cap.

[jasons2k]

srain can we get an updated about the weather tomorrow with the new model runs?

Tidbit from NWS:

/ISSUED 1004 AM CST Fri Feb 9 2018/

DISCUSSION...
Made only minor changes to the forecast on the morning update.
Still looking at cloudy skies today with highs warming into the
mid to upper 60s.

Latest available model guidance is still indicating an increasing
risk of locally heavy rainfall tonight through tomorrow morning,
and this is covered well in the grids. 42

[srainhoutx]

srain can we get an updated about the weather tomorrow with the new model runs?

The NAM/WRF ARW and HRRR runs suggest overnight showers and thunderstorms developing and increasing near sunrise across our Region. The model vary on exactly with neighborhoods/sections of SE Texas see the heaviest rainfall, but all the shorter range meso guidance paint a general 1 to 3 inch possibility depending on where the training storm develop.