San Juan weather/climate conversation with Joe Ramey ~ former NWS forecaster and now headmaster at Mountain Weather Masters


Hello MWM,

June is typically hot and dry, 2017 has been particularly so. After some measurable rain in the first week of June it has been dry. Convection the last few days have been high based producing mostly outflow winds and little rain. High based thunderstorms are expected with the Friday cool front.

Climate sites in the region are showing June 2017 temperatures well above normal, 4 to 7 degrees above which is a lot. Their precipitation totals are way behind normal on this the average driest month of the year.

No hints of the monsoon yet but conditions are developing as they should. As I have mentioned before, I believe it takes a near complete melting of the snowpack and a hot period to create regional thermal low pressure to suck in the subtropical moisture from the south. Snowpack in the San Juan, Rio Grande, and Gunnison river basins have basically melted out, while the central and northern mountains still have above normal snowpack. So we don’t know when yet but the monsoon moisture is on track to reach at least southern Colorado sometime in July.

In the latest outlook from the CPC, you can see they expect the heat to continue. There is also a dry signal for central-northern Colorado which may be due to the lingering snowpack.

Conditions in the Pacific are not changing much. The Nino 3.4 region along the equator is a bit warmer than normal. The weak forecast for a developing El Nino late this summer has changed. Now the best chances are for ENSO Neutral conditions into the fall season. ENSO Neutral are wild card seasons because there is no forecast tendency. If El Nino does develop later this year, the best forecast for now is for a weak event. Further north in the Pacific, the northern basin remains warmer than normal but well below 2014-2015-2016.

From those climate signals as well as climate change signals, you can see the CPC shows a strong warm signal for the next 12 months. The long-range precipitation outlook shows lots of EC (Equal Chances) or low forecast skill. There does seem to be a signal for a good monsoon season through the rest of the warm season. There is also a dry signal for the northern Rockies next winter, perhaps a remnant of the El Nino forecast. There is also a dry signal for the Desert SW into the Four Corners next spring.

Stay cool out there.
Practice lightning safety.

Joe Ramey

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