The number of homes under contract to sell increased in May.

It's the fourth straight month in which sales volume increased, corroborating the growing notion that housing is on the mend in most U.S. markets.

Consider these other housing-related stories from the past month:

• Existing Home Sales are rising
• New home supplies are falling
• The Case-Shiller Index is turning positive-like

Put it all together and it looks like the housing market is about to reach its bottom (if it hasn't already).

But just because homes are going under contract to sell doesn't mean that they actually will sell. A "deal" can fall apart for all sorts of reasons including failed home inspections, buyer-seller disputes, and mortgage-related problems.

In general, though, as the number of pending contracts increase, we find that Existing Home Sales rise, too, some 45-60 days into the future. And so long as buyers' demand for homes remains strong, we would expect that home prices edge higher.

It's too soon to say that housing has turned the corner for certain, but there's an awful lot of data lately that suggests that it has.

Tuesday -- for the first time in a long while -- members of the press met the monthly Case-Shiller Index data with enthusiasm. And why shouldn't they? 19 of the 20 measured markets showed a slowing pace of home price decline in April.

Here are some of the headlines about the story:

• Case-Shiller Home Prices Decline Only 18% (Business Week)
• Case-Shiller Less Bad (Seeking Alpha)
• Home Prices In 20 Cities Drop Less Than Expected (Bloomberg)

Now, the headlines feel negative, but they're actually highlighting some key strengths in April's figures. For example, nearly half of the Case-Shiller markets posted gains in April and all but one showed month-over-month improvement.

It's a step in the right direction but doesn't mean that housing has turned around for good.

We have to be careful about how we interpret the Case-Shiller Index because it's an imperfect housing gauge. The most obvious Case-Shiller flaw is that it only measures home values in 20 cities nationwide and they're not even the 20 biggest cities.

Houston, Philadelphia, San Antonio and San Jose are excluded from the report and each ranks among the country's 10 most populous areas.

That said, the report is still important because the Case-Shiller Index identifies broader housing trends and that helps to shape economic policy.

Not only versus last month but also versus last year, the pace at which home values are falling appears to be getting slower. This is the third straight month Case-Shiller has reported as such.

Now, three months makes a trend, but the data has to stay strong through the summer months to mark a bona fide turnaround. If the Case-Shiller Index shows strength for May and June, it could be the signal for which the markets have been waiting.

• Some said housing would rise
• Some said housing would fall
• Some said mortgage rates would rise
• Some said mortgage rates would fall

And nobody predicted just how big the government's stimulus package would be.

Now, on June 30, with the year officially half-over, it's as good a time as any to remember that people are much better at interpreting the past than predicting the future. Economists can make educated guesses about the future, but they're guesses nonetheless.

It's like watching the Weather Channel. A meterologist can look at the data and say it's going to rain next week, but the forecast is never 100%.

So far this year, mortgage rates have been up and down, credit availability has been higher and lower, and home prices have varied immensely from neighborhood to neighborhood. These are not the types of predictions we get from the pundits.

There's another 6 months until 2010 and there's no reason to expect the current trends to change.

The world is unpredictable and so is the U.S. economy. Therefore, consider making your personal finance decisions based on the information at hand today instead of on an educated guess about the future.

After all, the weatherman's been wrong before.

Aside from trader momentum, 3 market-moving events helped set the pace last week:

1. Housing data hinted at strength
2. Jobless data showed softness
3. The Fed said growth appears on-track

The combination of the three created volatility that -- for just the second time in the last 8 weeks -- worked in favor of rate shoppers.

Mortgage rates changed a lot last week, but they trended lower overall.

Already, however, markets are looking ahead to this week's holiday-shortened trading sessions. There is a ton of data to be released and as the week progresses, the ever-falling market volume could create some wide swings in mortgage rates.

The mystery is whether rates will be getting better or worse.

On Tuesday, markets will get Consumer Confidence and Case-Shiller Index data at 9:00 AM ET. The Case-Shiller Index is a home price measurement and it always gets a lot of press. Strength in either number should lead mortgage rates higher. Weakness should help rates ease.

Then, on Wednesday, Crude Inventories should take the spotlight. Normally, we don't watch this data point too closely but with gas prices easing last week, rising oil supplies could mean even lower gas prices ahead. This is anti-inflation and a good sign for mortgage rates.

And lastly, on Thursday, the government releases June's jobs report. This report is always a market-mover -- good or bad. And with trading volume low by Thursday, mortgage rates should move more than "normal".

Be ready to lock at a moment's notice this week. Mortgage rates continue to be volatile and the holiday-shortened week won't do anything to counter that. If you're the nervous type, when you see a rate that fits your budget, consider locking it in.

According to the Census Bureau, the supply of newly-built homes for sale fell to 10.2 months in May, its lowest level in 10 months.

Unfortunately, the New Homes Sales story wasn't positioned as a positively by the press. Instead, the most common headline on the data read "New Home Sales Dip 0.6%" with many journalists referring to the figures as "weak" or "disappointing".

Only, that's not completely true.

See, one of the nice elements of the monthly New Home Sales report is its footnote section in which the Census Bureau talks about statistical Margin of Error and that section tells us that if the Margin of Error is larger than the measurement itself, the report is useless.

And that's exactly what happened in May.

New Home Sales were measured to have fallen by 0.6 percent but that data point was dwarfed by its 17.8 percent Margin of Error, The "headline data", in other words, was just a guess.

The press reported it anyway.

Nonetheless, as it relates to the economy, falling home inventories are a positive. Having 10-plus months of homes on the market is still high historically, but a definite improvement over what we saw earlier this year.

So long as low mortgage rates and aggressive pricing persists from builders, we expect even less supply in the months ahead.

The Fed also reiterated its plan to support the mortgage market to the tune of $1.5 trillion.

In its press release, the FOMC noted that the U.S. economy is not slowing with the same speed versus just two months ago and that financial markets, in general, are improving.

These are two signs that the country may be emerging from recession, if it hasn't already.

The news isn't all good, however. The Fed made a point to highlight the potential hazards the nations faces on its path to economic recovery:

• The prices of energy and commodities have been rising
  
• Job losses are still mounting nationally
  
• Businesses are reducing capital expenditures
  

Also in its statement, the Fed acknowledged a plan to hold the Fed Funds Rate near zero percent "for an extended period" and a re-commitment to the U.S. Treasury and Mortgage Bond markets.

Market reaction to the Fed's press release has been muted.

With no new stimulus and no new "tools" to spur the economy unveiled, Wall Street is business as usual. Mortgage rates are unchanged post-FOMC today.

The FOMC's next scheduled meeting is August 11-12, 2009.

According to the National Association of REALTORS, the number of homes sold in May increased for the third straight month and the national housing supply fell by 5 months.

Furthermore, first-time home buyers are accounting for nearly one-third of the market activity.

But, before we declare a bottom in housing, it's important that we remember the First Rule of Real Estate:

All Real Estate Is Local

National housing statistics like Existing Home Sales are painted with a very broad brush. They lump disparate locales such as San Francisco and Seattle into one sample set and don't account for regional differences, let alone neighborhood ones.

Furthermore, getting down to a city-by-city, or even street-by-street basis, we can always find homes that are selling quickly and home that are languishing. Real estate is highly local and subject to countless influences.

That said, the national data isn't completely useless. From the patterns, we can infer that low mortgage rates, ample home supply and available tax credits are providing a quantifiable boost to the broader real estate market.

And based on recent pending sales data, we can expect June and July's Existing Home Sales figures to be similarly strong to May.

Therefore, if you're in the market for a new home right now -- or plan to be soon -- be conscious of home inventory levels in your target neighborhoods. Fewer homes on the market usually means less ability for buyers to negotiate and that leads to higher sales prices.

Plus, the NAR is reporting buyer activity up 10 percent from last year.

The housing market may not be fully recovered in every housing market just yet, but in studying the data, a lot of the pieces appear to be falling into place.

It's one of 8 scheduled meetings for the Federal Open Market Committee this year.

When the FOMC meets, it discusses the financial and economic conditions around the country and, when appropriate, the group makes new policy meant to speed up or slow down the economy.

The main tool for reaching this goal is the Fed Funds Rate and, earlier this year, the FOMC lowered it to "near-zero" percent in an attempt to stimulate growth.

But the Fed has other tools at its disposal, too, not the least of which is its $1.25 trillion pledge to the mortgage markets.

Now, if you'll remember, the Fed made that pledge in two parts:

• Part 1 came in November 2008 for $500 billion
  
• Part 2 came in March 2008 for $750 billion
  

After each announcement, mortgage rates reflexively dropped and stayed low for a period of a day or two. Then, fears of inflation set in on Wall Street, causing mortgage rates to pop back up because inflation is a mortgage-rate killer.

The Fed isn't expected to increase its mortgage market commitment this week, but because mortgage rates are above the government's "target zone", it's possible that the FOMC uses its post-meeting press release to give markets some guidance and its plan for the next several months.

A statement like this could alternately raise mortgage rates or lower them, depending on what the Fed says.

It's for this reason that floating a mortgage rate through tomorrow afternoon is extremely risky. The Fed could say nothing about mortgages, or it could say a lot. Either way, a small, quarter-percent change in mortgage rates can add tens of thousands of dollars to the lifetime cost of a person's pending home loan.