500mb anomalies show steadfast high pressure across the far upper latitudes, with negative height anomalies in the northern Pacific. NAM instability projections above have CAPE exceeding 5000 j/kg in northern Oklahoma by Friday evening, an incredibly high amount of instability for any time of the year. Instability exceeds 4000 j/kg in some parts of this region, and a formidable mid-level jet streak rounding the base of an upper level low in southern Illinois may provide for the opportunity for some organized convection among expected pulse storms. The deep troughing is likely due to an increased stream of storms that have been shifting across the northern Pacific. Northern cold winds start to pick up and meet the warm winds of the tropics, bringing rain. After a warmer ending to March, it is expected that a cold air mass will deliver one of the last punches of wintry weather to the country.

So when the air is not saturated the two thermometers show different readings, when the air is saturated the two thermometers show the same readings. The Z500 isopleths that exhibit the maximum extent (Figure 2d) do, however, show significant positive trends. Right now, the AAM tendency is positive, and this fits well with the current observation of a slight positive AAM. On another note, if you look closely, you can see a swath of positive height anomalies between the 150W and 120W markers between the numbers 10 and 20 on the left side of the image. On a side note, as the cold weather makes a very unwelcome return, it just so happens that I may be coming down with a little something. Should the MJO continue to work its magic with the West Pacific, there is little reason to think that this cooling trend in the waters of the North Pacific will not continue. Instead of running their mouths, Haters really should do a little research and learn the facts.

The September 24th 500mb height chart below shows how good of a match the two images are, further helping the argument for blocking in the next 10-30 days. A test on 233 carboxyl, 12 cysteine, 45 histidine, and 24 lysine pKa values in various proteins shows a root‐mean‐square deviation (RMSD) of 0.89 from experimental values. To the north of the Gulf Coast, CAPE values are less opportunistic, despite the increased wind shear. But we are just a week or two away from what could be a sizable shift in the temperature trend. This represents a trend of ridging across the Gulf of Alaska, which appears to eventually weaken and shift west. This above normal tropical activity in the West Pacific has greatly helped in the negative SST anomaly trend in the north central Pacific, which we discussed earlier. This brings about a pattern similar to the negative-PNA pattern that we have discussed rather extensively in this post, and seems to encourage the idea that the pattern forecasted to end May could continue into the opening portion of June.

Predominantly warm weather is expected to persist through the end of March. In a nutshell, this means very cold weather is expected about 6-10 days later, likely in the very final days of March and the first week or so of April. The last few days of March and first week of April could see a shot of rather strong cold weather. This development has occurred only very recently, and it was only a few weeks ago that the entire northern Pacific was well above normal in SST anomalies. The continuing storm train over the northern Pacific, aided by a favorable Madden-Julian Oscillation (which we will discuss more in-depth later), should assist in further lowering sea surface temperatures across the waters in and southeast of the Bering Sea. This fits in well with ensemble projections of a lowering EPO in the long range, which could lead to chillier temperatures for the United States.

There is a large body of below normal sea surface temperatures stretched from the Aleutian Islands to waters well offshore of the Pacific Northwest. Depending on if this Gulf of Alaska ridging does set up, the East US may have some trouble with maintaining more seasonal temperatures. Despite that potential, a decisively negative PDO pattern has been present recently, and this could discourage such cold weather in the East and Central US. By Saturday evening, the sector of instability has been shunted east into the states of Louisiana, Arkansas and Mississippi, among others. Short range model guidance indicates we will begin seeing a reservoir of instability be pulled up en masse from the Gulf of Mexico, a rather common occurrence for this time of year. Well, in the short term, expect this very wavy jet stream to continue, due mainly to the continuing storm train across the northern Pacific. Despite this impressive statistic, upper and lower level wind support again looks marginal, though slightly improved over the environment in the Midwest and northern Plains. This will help take your mind off the workout (just do not forget to hold your hips level throughout the workout and use isometrics with your arms to up the resistance and workout intensity like never before).