January: Increasing Clouds/Rain & Warmer To End Month

[tireman4]

Early morning 6am or early morning 2am?

Exactly at 2:38.25 AM...lol... your guess is as good as mine...

Umm you missed it, it is 2:38:31. Dang it Steve, you know better. LOL. Wxman57 is able to get it down to the minute ( reference last year's cold front in February 2011).

[srainhoutx]

With respect to longer range, the models are all over the place with respect to the teleconnection indices. I tend to side with the European, which at 0z has a slightly negative NAO, slightly negative AO, and negative EPO at days 8-10. What we need is a +PNA to get things going, but I see nothing to suggest that will come to fruition, yet. Perhaps Srain can offer some words of wisdom and HOPE.

No agreement with the GFS and Euro ensembles at all. Also no agreement with what the MJO is going to do either. There is a mountain torque propagating W from Asia. If the models can't get the pattern right with some help from WSR (Winter Storm RECON) 3-5 out, it's difficult to believe they have any real clue in the longer range. That said, I suspect winter is not over for those of us in the West and the Plains including Texas...

PRELIMINARY EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
900 AM EST MON JAN 23 2012

VALID 12Z FRI JAN 27 2012 - 12Z MON JAN 30 2012

LARGE-SCALE MODEL AGREEMENT IS QUITE GOOD THIS CYCLE...WITH THE
MEDIUM RANGE PERIOD OVER NORTH AMERICA BEGINNING WITH A WEAK BLOCK
OVER NUNAVUT THAT FAVORS A SPLIT-FLOW REGIME OVER THE
CONUS...WHICH THE DETERMINISTIC SOLUTIONS RESOLVE.
HOWEVER...IMPORTANT SOLUTION DIFFERENCES EXIST WITH THE SPLIT
PATTERN...PARTICULARLY WITH A CLOSED LOW CROSSING TEXAS STARTING
DAY 3/THU. THE 00Z ECMWF HAS THE STRONGEST SUPPORT FROM THE
DETERMINISTIC CONSENSUS AND THE GLOBAL ENSEMBLE MEANS...WITH THE
PARALLEL GEFS MEAN NOT QUITE AS SLOW AS ITS OPERATIONAL
VERSION...WHILE THE 00Z GFS/UKMET ACCELERATE TOWARD THE FAST SIDE
OF THE GUIDANCE REACHING THE EAST COAST BY DAY 4/FRI. ALTHOUGH
MODELS HAVE TRENDED FASTER...CLOSED LOWS HAVE A TENDENCY TO MOVE
MORE SLOWLY THAN PROJECTED. THUS...PREFER TO EXCLUDE THE FASTER
GFS/UKMET FROM THE PREFERENCES...WHICH LEAVES THE ECMWF AS THE
PRIMARY CHOICE.

STARTING DAY 5/SAT...THE BLOCK OVER NUNAVUT IS EXPECTED ERODE AND
EVENTUALLY BECOME REPLACED BY A BROAD TROUGH EXTENDING SOUTHWARD
TOWARD THE PLAINS. DETERMINING THE PRECISE DETAILS OF THIS GRADUAL
PATTERN CHANGE...ALONG WITH GROWING UNCERTAINTIES DEVELOPING OVER
THE PACIFIC...
CONFIDENCE FALLS DRAMATICALLY FROM DAY 5 ONWARD. THUS...THE
PREFERENCE IS TOO MOVE QUICKLY TOWARD THE ECMWF ENSEMBLE MEAN
THEREAFTER. THE 00Z GEFS MEAN IS CLOSE IN PHASE AND THUS IS AN
ACCEPTABLE ALTERNATIVE DESPITE ITS SLIGHTLY LESS PREFERRED SPATIAL
RESOLUTION.

[srainhoutx]

Early morning 6am or early morning 2am?

Exactly at 2:38.25 AM...lol... your guess is as good as mine...

Umm you missed it, it is 2:38:31. Dang it Steve, you know better. LOL. Wxman57 is able to get it down to the minute ( reference last year's cold front in February 2011).

He's a Pro and I'm just a lowly amateur enthusiast...what the heck do I know... ...

[tireman4]

Umm you missed it, it is 2:38:31. Dang it Steve, you know better. LOL. Wxman57 is able to get it down to the minute ( reference last year's cold front in February 2011).

He's a Pro and I'm just a lowly amateur enthusiast...what the heck do I know... ...

LOL. You are always rocking in our books sir.

[srainhoutx]

The 12Z GFS still suggests a closed core upper low near the Big Bend Region dropping ESE into Central/SE TX. The GFS is rather progressive which may be a bit too fast for what we've seen with these type storms since November. The GFS does suggest the heavier rains will be N of the Houston Metro, but there are 'hints' of a meso developing N of the Coastal low just to our W early on Wednesday. Rainfall totals are a bit higher than over night runs suggested with some 5+ totals showing up through hour 84.

[Andrew]

The 12Z GFS still suggests a closed core upper low near the Big Bend Region dropping ESE into Central/SE TX. The GFS is rather progressive which may be a bit too fast for what we've seen with these type storms since November. The GFS does suggest the heavier rains will be N of the Houston Metro, but there are 'hints' of a meso developing N of the Coastal low just to our W early on Wednesday. Rainfall totals are a bit higher than over night runs suggested with some 5+ totals showing up through hour 84.

Looks like a great setup. I am getting the Grlevel 3 ready.

[sambucol]

When are we going to get some cold weather? Anything wintry?

[wxman57]

When are we going to get some cold weather? Anything wintry?

Winter weather here with Wednesday's system? Not a chance. Air aloft is much too warm for anything but rain.

Here's a meteogram based on the 6Z GFS.

[MontgomeryCoWx]

Ed:

Can you tell me how to read that graph when looking for Severe Weather?

[Andrew]

Heavy rain and a tornado or two WEdnesday morning?

Helicity and EHI looks very supportive. At least for the possibility of a moderate Tornado/super cell... As srain was saying Wednesday looks like the best time period.

[srainhoutx]

The 12Z Canadian is much slower than the GFS (12 hour or so) with the U/L and keeps wrap around moisture going into Thursday as that upper low finally passes off to the E.

[wxman57]

12Z GFS is done. Here's an updated meteogram for Houston based upon it. Heaviest rain and greatest severe weather threat from mid morning through mid afternoon across Houston.

[Andrew]

Ed:

Can you tell me how to read that graph when looking for Severe Weather?

While my knowledge for severe weather is still in the works there are a couple of things i look at. If you notice the two lines on the Skew-T are really close together on the diagram. This represents a really saturated atmosphere (most of the way up). That leads to high rain rates and helps in producing stronger storms. That is probably the most basic thing to look at. After that you can examine things such as CAPE and CAP (which is an inversion http://www.stormtrack.org/library/forecast/cap.htm ). Then you can look at Helicity http://en.wikipedia.org/wiki/Helicity_(fluid_mechanics) and some other aspects that help with rotation in the atmosphere. I am still learning myself but ED may be able to go into more detail. For CAPE, CAP, and Helicity those numbers are off to the right. I wish I could explain more but I have to go.

[Ptarmigan]

Whats the mean PW rate in January for Houston?

The link below has a nice statistical breakdown of PW values from all of the radiosonde sites around the Nation. Unfortunately there is no site for Houston but I think the Lake Charles data would be a close enough representation of what we see here locally on average.

http://www.crh.noaa.gov/unr/?n=pw

As you can see from the LCH data, PW's around 1.50'' would be 2SD above normal and with several models forecasting values to possibly peak around 1.55-1.6'' that would put the values around the 99th percentile.

I noticed the highest PW is in July, August, and October. Here is a list top 50 PW values.
http://www.crh.noaa.gov/images/unr/soo/pw/pw_Top50.pdf

Code: Select all

Rank PW (in.) Year Month Day Hour (Z)
1 2.80 2010 8 18 12
2 2.77 1995 10 3 12
3 2.77 1963 7 11 0
4 2.70 1998 9 12 0
5 2.67 2006 10 16 12
6 2.67 1998 9 11 17
7 2.64 1989 8 1 12
8 2.63 2010 6 30 6
9 2.63 1998 9 11 0
10 2.62 2010 8 19 12
11 2.62 2008 8 5 12
12 2.62 2006 10 17 0
13 2.61 1969 7 11 12
14 2.60 2010 7 1 0
15 2.60 1982 7 30 0
16 2.59 2010 7 19 12
17 2.59 2008 9 13 12
18 2.59 2005 9 24 0
19 2.59 1989 8 22 12
20 2.58 2011 7 26 12
21 2.58 1998 9 12 12
22 2.57 2010 8 18 0
23 2.57 2010 7 27 12
24 2.57 2010 7 19 0
25 2.57 2004 7 29 12
26 2.57 2001 6 7 12
27 2.57 1985 8 16 0
28 2.56 2011 7 28 12
29 2.56 2010 8 12 12
30 2.55 2010 8 16 12
31 2.55 2006 8 26 12
32 2.55 2003 9 22 0
33 2.55 2000 9 2 0
34 2.55 1990 6 12 0
35 2.55 1962 8 29 12
36 2.54 2010 7 1 12
37 2.54 2002 9 20 0
38 2.54 2001 7 15 0
39 2.54 1987 8 10 0
40 2.54 1977 8 30 0
41 2.53 2011 9 4 0
42 2.53 2011 7 15 12
43 2.53 2006 8 23 0
44 2.53 1998 9 11 12
45 2.53 1995 8 5 0
46 2.53 1973 9 5 0
47 2.53 1969 7 19 12
48 2.52 2011 8 1 12
49 2.52 2010 8 20 0
50 2.52 2010 8 13 12

Interestingly the highest PW occurred in August of 2010 and there were no huge rain events that time. Interestingly, the low temperatures were unusually warm, which made August 2010 the warmest despite having just three days of 100 degrees. Ike also has one of the highest PW on record. Strangely, I don't see Claudette (1979) or October 1994 in the top 50. I looked at the high PW days and there was no rain for the most part. September 1998 was due to Frances, while October 2006 we had flooding rains. August 1989 was from Chantal.

That PW data from the link is from 1948-2011 and over Lake Charles. Would be cool to see it over Houston. You can see PW values at this link.
http://www.esrl.noaa.gov/psd/data/composites/day/

I saw Ike and the PW is over 2 inches! Same goes with 1979 Claudette and October 1994 flood.

[svrwx0503]

No big changes in thinking this morning after looking over the 12z model progs. Excessive rainfall/flooding continue to look like the greatest threats with isolated tornadoes and damaging wind gusts coming in second. Model soundings continue to indicate plenty of shear and enough instability for mid-winter to produce a notable risk of severe weather, especially in cells which can develop out ahead of the main complex. It looks like the conditions for severe weather will be maximized during the morning hours on Wednesday from about 6am through noon with the main event/heaviest rainfall looking to come through between about mid-morning and early afternoon.

In regards to who may see the greatest rain totals, it will likely be one of those wait and see events as conditions for training storms will be possible across the entire region. The northern sections might have a slightly higher risk since it is possible the retreating warm front will pull up stationary across those areas before moving back southeast with the approach of the main storm system. My feeling is that we will likely see some scattered activity developing overnight Tuesday along and south of the warm front, continuing into the morning hours with stronger/more organized convection firing across central/north Texas, possibly extending into northern and western sections of southeast Texas. The entire system should then move across the remainder of the area from mid-late morning into the early afternoon bringing with it the highest risk for flooding rains across metro Houston, especially in areas that see the stronger storms during the overnight and early morning hours.

[txflagwaver]

Early morning 6am or early morning 2am?[/quote]

Exactly at 2:38.25 AM...lol... your guess is as good as mine...

Umm you missed it, it is 2:38:31. Dang it Steve, you know better. LOL. Wxman57 is able to get it down to the minute ( reference last year's cold front in February 2011).

He's a Pro and I'm just a lowly amateur enthusiast...what the heck do I know... ...


HA HA HA..I am asking as in overnight storm like Alabama got hit with..more dangerous coz folks are sleeping..or in daylight..still bad but at least you can see them coming..you guys are SO funny

[wxman57]

12Z GFS has a PW for IAH of 1.61" at noon tomorrow. That looks to be the peak. 1.52" at 9am and down slightly to 1.58" at 3pm. WAY down by 6pm as NW flow and drier air moves in (1.23" and falling fast).

[Ptarmigan]

Looking at this week's event, looks to be more severe with heavier rain than two weeks ago.

[srainhoutx]

For what it's worth, the 12Z GFS ensembles suggest a slower ejection E with the upper low...

[srainhoutx]

The 12Z UKMet suggests more phasing with the northern stream energy and moves the U/L NE a bit quicker. The UKMet does suggest SE TX will see heavy rains/storms on Wednesday...