Category: Ask Dr. Bob

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Why does Dr. Bob sign off, “I’m Dr. Bob Peters and that’s thirty”?

ANSWER
In the days of linotype machines for setting type, multiple pages of copy contained the footer “-more-” at bottom of each page. The end of the copy on the last page carried the footer “-30-”. That told the typesetter in a definitive fashion that he had reached the end of his copy. Why “30″? No one I have ever asked knows. But the designation “30″ has stuck as an indication of “the end”.

Dr. Bob adopted this convention years ago when he was a neophyte broadcaster.
Hope this answers your question. Thanks for listening to us and thanks for taking the time to write.

Paul L. Gleiser
President

Ask Dr. Bob: Seems most of the fronts/thunderstorms arrive in Tyler around 5:00am.

Ask Dr. Bob: Seems most of the fronts/thunderstorms arrive in Tyler around 5:00am.

ANSWER

No, Sir, not that I know of; the past several have, indeed, arrived at about that time; this is part of the reason why we’ve had very little severe weather thus far this season.
About the only thunderstorm pattern is that there does seem to be a worldwide thunderstorm maxima at about 2200 GMT each day–in other words, late-afternoon here.
By the way, it looks as Thursday morning’s front will be showing up right around daybreak.
RKP

Ask Dr. Bob

Ask Dr. Bob: Why do we hear both terms “wind” and “winds”?

Ask Dr. Bob: Why do we hear both terms “wind” and “winds”? Isn’t wind singular, as in “wind is out of the southwest” instead of “winds out of the southwest”? Just a curiosity that came to me this morning.

ANSWER:

This is a very good point; I think, like much else in English, there is no rational basis for the interchangeability of the two terms.
However, in writing, I think I follow this convention:
a) if I am speaking of the wind over a considerable period of time, i use the plural;
b) if I am referring to the current direction and velocity, I use the singular.
Another convention:
c) if I am using the noun preceded by either the definite or indefinite singular article followed by a singular verb, I use wind;
d) if I am using a plural article and predicate, then I use “winds.”
Thanks for this.
RKP

Do australia’s cold fronts come from antartica and are they like ours?

Do australia’s cold fronts come from antartica and are they like ours?

ANSWER:

Yes, they do. Theirs are not as intense as ours because theirs travel over about 2,500 miles of ocean before reaching land, while ours travel all of the way over land.
RKP

Why do you use millibars as a unit of measure and barometric pressure is measured with something else?

Why do you use millibars as a unit of measure and barometric pressure is measured with something else?

ANSWER:

It is the international standard; inches are only used in public NWS products; the remainder of the world (except for former Soviet countries) uses millibars, which has now been converted to hectopaschals; the former Soviet countries use millimeters, which medical products in the United States also use. Millibar is the most widely used measure, and is standard on all maps and discussion products.
RKP

What is your prediction for drought probabilities in 2013?

ANSWER:

I believe we’ll run snear to below normal in rainfall through about March; beyond that, the elong-range outlooks are taking us back to normal. This sounds pretty reasonable as there is no significant signature in the Equatorial Pacific. The one problem with this outlook: we do not yet fully understand the effects of a circulation called the “PDO”–Pacific Decadal Oscillation. That’s why sticking with a near normal rainfall outlook after March 2013 looks valid.
We’ll know this time next year!
RKP

Do sea breezes always blow toward beach, like in Corpus?

Do sea breezes always blow toward beach, like in Corpus? Seems that during a cold front, breezes would blow toward water.

ANSWER:

Sir,
When it is the sea-breeze, it blows landward; when the wind blows offshore as you are referring to, it is called the land-breeze. Thus during most of the year in Texas, the land-breeze blows at night, and the sea-breeze blows during the day. This is because the land is cooler at night, while the sea is cooler during the day.
RKP

Does the wind ever get over 5 MPH at Verkhoyansk, Russia?

Does the wind ever get over 5 MPH at Verkhoyansk, Russia? Everytime, any season, I look at their weather, the wind is calm or 2 MPH.

ANSWER:
Sir,
Russian stations report in MPS–meters per second; to convert that into miles per hour, multiply by nine-fourths; thus, a 5 mps wind velocity would about 11 mph. All stations in the former Soviet Union and many stations in the former Soviet block still use the mps wind velocity measurement, and measure barometric pressure in millimeters of mercury as opposed to inches or millibars.
As a better answer to your question, yes I believe that it would. I tried to find the station on the locater list so I could check their coordinates–as I do not really know where it is. I could not locate the station.
My guess is that the equipment is old and is not reading correctly. It would be highly unusual for a station to have wind velocities that low.
RKP

How do you know without a calendar that we are heading towards fall?

The best way is to note the sun angle at solar noon. Solar noon here is about 1:21 p.m. CDT; the sun angle decreases by about one degree every four days. What you could do is this: place a stake in the ground where it gets full sun, and measure the length of the shadow; then four days later, come back and it will be a little longer, and it will continue to lengthen until December 21.
The sun angle above the horizon at solar noon on June 21 is atout 80 degrees; on December 21 at solar noon (12:21 p.m. then because we’re back on standard time) is about 36 degrees.
RKP

If a named storm is in the Pacific and crosses to the Gulf of Mexico will it be re-named?

If a named storm is in the Pacific and crosses to the Gulf of Mexico will it be re-named?

ANSWER:

Yes, it is–and it has occasionally happened.
RKP

Could you explain this statement: “The 500-mb. Height is 590 dm and rising, so the warming-up persists.”

Could you explain this statement: “The 500-mb. Height is 590 dm and rising, so the warming-up persists.”

Answer

The 500-mb (millibar) height refers to the oint in the atmosphere at which the air pressure falls to 500 millibars–about 15.00 inches of mercury; the mean height for that is about 18,000 feet (about 5,500 meters or 550 dm–decameters.) If the height is greater, than it is hotter here because as air flows downward, it warms. Thus, 590 decameters is about 19,000 feet. This means upper air high pressure, downward-moving air (subsidence), and hot temperatures on the surface. During the intense heat of last Summer, the 500-mb. level was about 610 dm.
We use decameters instead of feet for the 500-millibar level because it is a smaller number, and the remainder of the world uses the metric system.
RKP

Regarding the thinning of the Arctic sea ice, what are your opinions on the weather effects it will have?

In reference to your earlier response regarding thinning of the Arctic sea ice, what are your opinions on the weather effects it will have? Specifically to satisfy my curiosities, I’m interested if it will result in higher year round temps or just higher winter temps, year round precipitation, and the seasons(longer or shorter seasons, early or late seasons).

ANSWER
Sir,
Here is my best answer:
a) I believe we will have higher precipitation; in fact, we use something called a “standard climate” in referring to normal. They are thirty-year averages, and are re-calculated every ten years. We’re currently using the 1981-2010 standard climate. When I started in the weather business, we were using the 1931-1960; our yearly average rainfall has laready increased by about two inches.
b) I think it will be more a matter of temperature extremes along with a slow rise in temperature. I’m a bit reticent to make temperature comparisons using the standard climate for Tyler since we have significantly urbanized since the climate I started with.
Beyond that, I don’t think I know enough to say anything with any degree of certainty.
RKP

I’m confused about the tropical storm names this season. I thought we went straight through the alphabet?!

I’m confused about the tropical storm names this season. We had Alberto, then Hurricane Bud. Now we have Tropical Storm Beryl. Where did Bud fit in? I thought we went straight through the alphabet?!

ANSWER:

Different oceans: in 2012, the Atlantic names begin with a masculine name (Alberto), then Beryl; the Eastern Pacific names begin with a feminine name (Aletta), and then Bud.
RKP

What is your forecast for the summer of 2012?

What is your forecast for the summer of 2012? Is this summer looking like a repeat of summer 2011 as far as temperatures and rainfall? It would be nice if we could just have a normal summer with average rainfall and temperatures.

ANSWER:

I do not believe this Summer will be as hot nor as dry as was last Summer. My reasoning: the LaNina period in the East Central Equatorial Pacific has broken down. That would suggest normal rainfall. The continued presence of dry soils over much of this part of the country suggests that temperatures will run somewhat above normal–but nothing like what we had last Summer.
The two weaknesses in my assumptions:
a) There is another circulation pattern called the Pacific Decadal Oscillation–a massive upper air pattern which covers much of the Northern Hemispheric Pacific Ocean. We don’t fully understand that yet; and
b) The models are not yet taking into account decreased Arctic Ocean sea ice caused by the global warming–which is a fact.
Still, I think precipitation between now and late-August should run between 7.0 and 10.0 inches; we will have some 100-plus days–but nothing like the fifty-eight we had last year.
RKP

What is the outlook for the remainder of the year (2012) …precipitation statewide?

ANSWER

Statewide: West Texas will likely continue in drought with easing later in
the year; East Texas: I expect near to above normal precipitation at least for the next two or three months–and probably beyond.

The forecasting models have not done well since December on precipitation in our part of the state. LaNina persisted until the middle of last month, which would have suggested below normal rainfall. Instead, we have had about 150 percent of normal precipitation since December 1.

NWS thinks the problem they are having with the models is not having factored in reduction in Arctic ice due to global warming.
RKP

Where are temp. and precip. measurements taken in the Tyler and Smith County area?

ANSWER

The observations for climate purposes (Tyler–City) are taken at my house on the south side. They are manual, and not automated.
RKP

Has winter been wetter than was forecasted this year and are we out of the LaNina pattern yet?

ANSWER

Answers:
a) Mean winter precipitation has been about 15 percent above normal;
December was quite wet, January near normal, and February below normal (thus
far); that for February is about to change;
b) We are emerging from LaNina; NWS thinks it will be early May before the signature completely goes away; however, one encouraging sign is that warm water is downwelling in the Central Equatorial Pacific. That means that sea-surface temperatures and ocean heat content will be rising; that, in
turn, means that we’ll have more Pacific moisture above 8,000 feet to perhaps bring us better rains than last warm season.
RKP

You mentioned transitioning to a Spring pattern next month.

You mentioned transitioning to a Spring pattern next month. Would you briefly expand on that situation.

ANSWER

Though it sounds early–it actually is not; the transition occurs because of greater sunlight and a higher sun angle; this precedes substantial surface warming by a few weeks–just as transitioning into a Fall pattern starts in mid-August–before we notice much change down here on the ground. The reason for the delay: the slowness of ground to respond with higher
temperatures to incresed sunlight, and vice-versa for the Fall transition. We call that characteristic “specific heat”.
RKP

Weather Question for Dr. Bob

Do you feel like the LaNina front is coming back or are just on the tail end as it moves out.

ANSWER:

Yes, I do believe we will have a weak to moderate LaNina this Winter–not as significant as last Winter. This would suggest near normal temperatures with below normal rainfall.

Weather Question For Dr. Bob

Do fall and winter hold any good news for rain in the East TX and DFW area?

ANSWER

You’re not going to like this. It appears as if precipitation will continue at or below normal well into the cool season. We’re going to be better off than we have been, but we’re not going to be making up our deficits. LaNina, though in weakened form, is forecast to persist. A new science called “dendrochronology”–determining previous weather conditions from tree-ring data, says that protracted dry periods have occurred in the past. We can trace our climate averages back to 1426. Our current dry period is comparable with that of 949-1956. That we have observations for. Prior to that, we go back to 1716-1725, and then 1450-1489. This is probably very much more than you wanted to know, but I’ve been reading about it lately and wanted to tell somebody.
RKP

Is there anything to suggest this heat will last through September? I’ve had enough.

ANSWER

There actually is some hope; the upper air high should go east of us late this week, giving us some rain–perhaps. If we get some rain, then we will cool for a few days. Also, I agree with you–I’ve had more than enough of it. Insofar as the entire month, the models are keeping our temperatures above normal. We’ll see.

RKP

I know all hurricanes rotate counter-clockwise and all typhoons rotate clock-wise but do tornadoes rotate in different directions or all the same?

ANSWER:

A bit of a correction. Hurricanes (Atlantic, Eastern Pacific, and Central Pacific Basin), typhoons (Western Pacific Basin) and cyclones
(Indian Ocean Basin) all rotate counter-clockwise in the Northern Hemisphere–and so do tornadoes. In the Southern Hemisphere, the rotation of all is clockwise. This is because of something called the Coriolis force.
RKP

Do you have any idea when we might get some relief from the nearly non-stop winds of the last few months?

Do you have any idea when we might get some relief from the nearly non-stop winds of the last few months? This is the windiest late winter and spring I can recall. It’s nearly June now. Surely this will stop some time…won’t it? I’m a fisherman, and every trip to the lake is a beating.

ANSWER

These winds are caused by storm systems migrating in slowly form the Pacific Coast, and then traversing the Plains very slowly; by the time they have reached the Mid-West, there is another on the Pacific Coast; after a day or two of respite, the process starts all over again.

Climatologically, they should let up in early June. By that time, the procession of storms across the Pacific has shifted well north of the United States. I see no reason to think that this will not happen this year, as well.
RKP

What has been the main driving force behind these cool fronts not making it this far south?

What has been the main driving force behind these cool fronts not making it this far south?..Here in south La. we’ve had consistant southerlies for the past 6 to 8 weeks that have been 6 to 12 mph higher than normal. I know this southerly wind flow has been feeding the midwest storms as they come through. Normally we get about 50% of these frontal boundaries through our area. We depend so much for spring rains around here. Summer rains normally come from tropical systems.

ANSWER
A strong upper air high pressure ridge, centered over South Mexico. This may be the result of the La Nina event of the past Winter. That event is winding down, and rainfall should return to normal at mid-Summer.

Why are some forecasters predicting a hurricane to hit the Texas coast this year (2011) with some saying it could be a major hurricane?

ANSWER

Weakening LaNina events tend to produce an active hurricane season in the Atlantic Basin. Attempting to accurately predict a landfall is a bit speculative.
RKP

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