Wednesday, April 23, 2014

Long Range Forecast Update for Late April, Early May

This is an update to a previous long range outlook concerning the expected weather for late April and into early May.

Tropical Tidbits
For the last days of April and in to early May, I'm still looking at above normal temperatures for a decent portion of the nation. Shown above is the 500mb height anomaly pressure forecast over the West Pacific for April 26th. In this image, we see a strong ridge of high pressure stationed over Japan and East Asia, permitting the flow of above normal temperatures into the area. This event has significant implications on our weather here in the US. There is a rule, well explained by Joe Renken, that states a weather phenomenon in East Asia will be reciprocated in the United States 6-10 days later. This means that if there is a storm system in Japan on a certain day, we can expect a storm in the US 6-10 days after that. The same goes for high pressure and warm weather. So, if we use that rule, we can expect warmth over the United States around the May 1-5 period, if not for a longer time period than that. 

Tropical Tidbits
By the end of the first week of May, I anticipate that we will see another cool-down for a few days as a closed low looks to move into Japan. Since this 500mb anomaly image is valid for April 29th, we can expect this cool-down to start showing itself sometime around the May 4-8 time period, though the timeframe could probably be extended to May 4-10 as the closed low sticks around Japan for a day or two more. Despite how long that timeframe may seem, the actual cold weather should only be around for a few days, not for this whole 6-day timeframe.

Tropical Tidbits
By the time we get to the second week of May, we're looking at another bout of sustained warmth, as the GFS ensembles bring about a ridge of high pressure over Japan and the waters surrounding the island nation. Ensemble guidance looks to have rather low confidence in this event, though we should get a more accurate look at this portion of the forecast in the next few days. 

To summarize:
• I am still forecasting warmer than normal weather for the last few days of April into very early May.
• Cooler weather looks to take hold near the end of the first week of May.
• Warm weather may return for the second week of May.

One final note, I received a multitude of arrogant responses to the previous long range outlook I had posted. Remember that every comment is moderated before it's published, and arrogant comments like the ones I've been getting for the last few days will not be published.

Andrew

10 comments:

Current Newsroom said...

You do great work. I remember how you had Sandy nailed down long before the "traditional" forecast guys joined in. Weather factors, conditions and results change daily if not hourly. Only God gets it right. We just try to warn everybody else.

Christopher Ebie said...

I find your posts interesting so keep up the good work.

steve said...

hello andrew -- i have been reading your forecasts for a while now, since discovering them while in florida for vacation. I am sincerly amazed at your record of probability. You are remarkable. If people are sending you lousy remarks, it can all be put down to jelousy.
I look forward each day for your outlooks and have been learning so much about the weather. I only wish you were doing the weather here in canada--what a treat that would be. Keep up the great work and don't let people bother you.

SteveM said...

As a longtime weather fan, I truly appreciate the work you put into these forecasts. I can't get this anywhere else. Your long-range forecasts have actually helped me plan some trips. Keep up the great work Andrew.

Anonymous said...

Your work is amazing, I have been following you for some time. Bravo to all your efforts. If you can provide some insight into our drought here in California for 2014, would like to hear what your opinion is. Will El Nino help us out this year?

Anonymous said...

Andrew since you equate arrogance with disagreeing . I will refrain from commentary.

I am really into the global climate scene and the man made global warming fiasco.


I am so sick of hearing about warmth in any shape form or manner. Nevertheless I think a good portion of the nation will have below avg. temp from now through early May.
Take Care

Andrew said...

I'm afraid you are mistaken in that aspect- I welcome disagreements, but there were nearly a dozen comments not seen that were more of the spam variety than disagreement. Nevertheless, we'll see how the forecast works out.

Anonymous said...

so what happened to this super el Niño that was supposed to be happening? The SOI for the past 30 days went from -12 to +4. We have never seen a very strong or a super el Niño with a rapid rise in April. You have become very quiet about this lately.

Anonymous said...

Was wondering how the current "Rex Block" set up and the crashing NAO will affect the forecast for warmth in the early part of May. We in New England have suffered through a horribly cold winter, and fairly chilly spring so far. Will New England, and especially southern NE ever get any sustained warmer weather? Or are we destined to remain below normal?

Anonymous said...

Andrew , I think the summer like warmth you had expected for late Apr/May is not taking place for the most part.

I also agree with the previous poster perhaps El Nino but nothing like 1998.

I have learned much about the tools used for forecasting by reading all of your post. Very educational . Thanks.

Although I am more into the climate aspect of things and have some interesting theories.